Our guest blogger is Jessica Arons, director of the women’s health and rights program at the Center for American Progress.

Today’s historic Supreme Court ruling upholding the Affordable Care Act, otherwise known as Obamacare, is a tremendous victory for millions of Americans, and perhaps most of all for women. By upholding the health reform law, the Supreme Court will allow significant reforms to our health insurance system to be fully implemented, helping to keep health care costs down and protecting Americans from the health insurance industry’s worst abuses.

Here are the top 5 ways Obamacare helps women:

1. Women will no longer be denied insurance coverage for gender-related reasons. In today’s insurance market, it is common for insurers to refuse to cover women because of gender-based “pre-existing conditions,” such as having had a Cesarean section or being the victim of domestic violence or sexual assault. Thankfully, this practice will be outlawed under Obamacare in 2014. In the meantime, adults with pre-existing conditions who have been uninsured for at least six months can purchase affordable coverage through temporary Pre-existing Condition Insurance Plans.

2. Women will no longer be charged more for their insurance coverage just for being women. Under a practice known as “gender rating,” insurers currently charge women higher premiums—up to 150 percent more—than men for identical health benefits. As a result, women now pay $1 billion more than men each year for the same health plans in the individual market. As of 2014, however, under the Affordable Care Act, gender rating will become illegal in all new individual and small group plans.

3. Maternity care will be required in new insurance plans. Coverage for maternity care—health care that only women need—is routinely excluded in the individual insurance market. Only 12 percent of plans sold in the individual market even offer maternity coverage, which is frequently inadequate because of waiting periods or deductibles that can be as high as the cost of the birth itself. But once Obamacare is fully implemented in 2014, about 8.7 million women will have guaranteed access to maternity care in all new individual and small group plans.

4. Women will be guaranteed coverage of preventive services with no cost sharing. More than 50 percent of women have delayed seeking medical care due to cost, and one-third of women report forgoing basic necessities to pay for health care. But under the health reform law, insurers are now required to cover recommended preventive services such as mammograms, Pap smears, and well-baby care without cost sharing. More than 45 million women have already taken advantage of these services. And starting this August more services, including contraception, gestational diabetes screening, and breastfeeding supports, will be added to the list of preventive care that must be covered at no additional cost.

5. Women will gain better access to affordable health insurance. Starting in 2014 women and their families, as well as small businesses, will receive tax credits on an income-based sliding scale to help purchase insurance coverage. This will help individuals who earn up to $43,000 per year and up to $92,200 for families of four. Also in 2014 up to 10.3 million women will gain insurance coverage when Medicaid expands its income eligibility to include people with incomes below 138 percent of the federal poverty level—less than $15,000 for individuals and about $31,809 for a family of four in 2011. The health law also eliminates Medicaid’s categorical requirements, so that low-income women who meet the income requirements can be enrolled even if they have no children and are not pregnant.

To learn more about the benefits of Obamacare for women, see the Center for American Progress report, “Women and Obamacare.”

Responding to Thursday’s Supreme Court decision upholding the constitutionality of the Affordable Care Act, Congressional Republicans have scheduled a vote in the House to repeal the law and Mitt Romney pledged to undo the measure if he’s elected president in November. But unless the GOP wins a super majority in the Senate — a scenario no one thinks is plausible — it can do little more than weaken Obamacare’s regulations and defund some of its provisions. Here is why:

1) Romney has no authority to issue waivers. Romney has promised to expand a provision of the Affordable Care Act that allows states to opt out of certain sections of the law to permit states to ignore it entirely. But the executive branch and the Department of Health and Human Services (HHS) likely don’t have the authority to grant such broad waivers. According to the law, HHS (together with the IRS) have waiver authority, but only if the states meet very specific requirements. Neither have blanket waiver authority, which would have to come from Congress. Sen. Ron Wyden (D-OR) — the author of the waiver provision — has challenged Romney’s claims, saying, “Anybody who tries to move outside the standards of the bill — which is the coverage and costs and the like — well I’ll certainly fight that. But I think lots of other people will too.”

2) Congress can’t repeal the full law through reconciliation. Without the necessary 60 votes in the Senate for full repeal, Republicans are pledging to use a budget reconciliation bill to undo the ACA. But this process would only apply to the budget-related elements of the law and would thus leave many portions — including the mandate — intact. As health care expert Robert Laszewski put it, “Romney could end up creating a chaotic environment driven by enormous uncertainty over just which parts of the new health care law would be implemented–for consumers, health care providers, and insurers.”

3) Republicans have nothing to replace it with. David Frum explains that since the expansion of coverage provisions go into effect in 2014, Romney would have just one year to both repeal and replace the law. Republicans haven’t even coalesced around a single plan — and many in the party believe that the federal government should leave health care alone and want to leave the entire reform process to the states. Thus, “if replacement does not happen in the first 100 days, it won’t happen at all—that is, it won’t happen as a single measure, but rather will take the form of dozens of small incremental changes adopted episodically over the next 20 years.”

4) Americans support Obamacare’s provisions. While Americans may not like “Obamacare” — and the political process of passing it — they do support its major provisions and are likely to resist any effort by Republicans to take away their benefits. A recent Reuters/Ipsos poll found that while 56 percent of Americans oppose the law as a whole, 61 percent of respondents favored allowing young adults to stay on their parents’ insurance plans until age 26, 72 percent wish to maintain the requirement that companies with more than 50 workers provide health insurance for their employees, and 82 percent of respondents favored banning insurance companies from denying coverage to people with pre-existing conditions. As more benefits roll out in 2014, it will be increasingly difficult for Republicans to argue for their repeal.

Following the Supreme Court’s ruling to uphold the Affordable Care Act, Sen. Jim DeMint (R-SC) condemned the law as “an unprecedented and enormous tax.” Surprisingly, he also called on states to ignore the ruling and stop implementing the ACA’s exchanges. Interestingly, that would lead to the federal government stepping in:

“I urge every governor to stop implementing the health care exchanges that would help implement the harmful effects of this misguided law. Americans have loudly rejected this federal takeover of health care, and governors should join with the people and reject its implementation.”

The Affordable Care Act requires each state to set up a health insurance exchange where consumers can purchase insurance, but if a state does not implement one, then the federal government will operate the state’s exchange program. Officials in several Republican-dominated states put off setting up their exchanges until after the ruling, and governors in three states — Florida, South Carolina, and Wisconsin — say they will not act to implement the law until after the November election if Mitt Romney is elected and tries to repeal the law.

States have until November to turn in their exchange plans to the federal government so that the state programs can be approved by Jan. 1, 2013 — and in place by Jan. 1, 2014. But for states like Georgia, where legislators have done nothing to set up an exchange, and other states that have chosen not to act, it’s unclear if officials can set up an exchange program in time to avoid intervention from the federal government.

WASHINGTON, D.C. — Businesses should be allowed to deny health insurance to cancer patients, according to a Republican senator, because “our nation was based on the foundation of freedom and limited government.”

Discussing health care outside the Supreme Court today, Sen. Ron Johnson (R-WI) told ThinkProgress that there “shouldn’t” be a law requiring businesses to cover employees who have cancer because that would “create an obligation” for others. “When you create a right for somebody,” Johnson said, “you create an obligation for somebody else, and then you’re taking away that person’s right.”

KEYES: I know Richard Murdock had said even though businesses should give people, for instance, with cancer, health coverage, they shouldn’t be legally required by the federal government.

JOHNSON: They shouldn’t. Listen, our rights are life, liberty, and the pursuit of happiness. And when we start expanding beyond that realm, when you create a right for somebody, you create an obligation for somebody else, and then you’re taking away that person’s right. And that maybe doesn’t seem all that great, but it’s just true. Our nation was based on the foundation of freedom and limited government.

Watch it:

Under Obamacare, health insurance companies cannot deny people health insurance because of a pre-existing condition like cancer. Johnson remains strongly opposed to the law.

Unfortunately, he is not the first person to suggest that businesses should be permitted to deny insurance to cancer patients. Last week, Indiana Republican Senate nominee Richard Mourdock similarly argued that employers should be allowed to deny coverage to cancer patients “if they want to keep their health care costs down.”

Steven Perlberg contributed to this report.

Now that Chief Justice John Roberts has authored the Supreme Court’s 5-4 majority opinion upholding the constitutionality of the heart of the Affordable Care Act, some conservatives may be tempted to criticize the George W. Bush appointee.

Here is a sampling of what leading Republicans have said about Roberts after Bush nominated him in 2005. All 55 Republicans voted to confirm Roberts:

Rep. John Boehner (R-OH): “Supreme Court Justices John Roberts and Samuel Alito, President Bush’s two successful appointments to the high court, are who we hoped and thought they were — Justices committed to a fair and just interpretation of the Constitution.”

Sen. Mitch McConnell (R-KY): “Judge Roberts because his position in a particular case did not mirror a Senator’s personal policy preferences, nor when it comes to a fair process should we require.”

Sen. Tom Coburn (R-OK): “I’m confident that Chief Justice John Roberts will help restore the Constitutional balance of power between the branches of government. Judge Roberts, I believe, will not attempt to write policy from the bench and will leave legislating to the Congress. …Judge Roberts proved himself during his confirmation hearing to be extraordinarily intelligent, highly-qualified and totally committed to applying the law justly.”

Sen. Jim DeMint (R-SC): “We need a Justice, not a super legislator — a Justice who will rightly interpret our laws, not create laws.”

Sen. John Thune (R-SD): “As we pay tribute to the legacy of former Chief Justice Rehnquist, we see many of the qualities that marked his tenure of excellence mirrored in Judge Roberts. …Judge Roberts brings with him a brilliant legal mind and a profound respect for the Constitution and the Court.”

Sen. Jeff Sessions (R-AL): “John Roberts’s confirmation was a defeat for the politicization of the courts and the notion that a judge should be an advocate for this or that view.”

Sen. John Cornyn (R-TX): “An exceptional judge, brilliant legal mind, and a man of outstanding character who understands his profound duty to follow the law.”

Sen. Roy Blunt (R-MO): “He has proven himself as a judge who applies the law impartially with an eye toward the strict interpretation of the Constitution, rather than legislating from the bench.”

Sen. Orrin Hatch (R-UT): “If I have ever seen anybody who deserves being on the Court more than John Roberts, I have to think pretty hard. John Roberts is a fine man.”

Frmr. Sen. George Allen (R-VA): “I found Judge Roberts to be a well-grounded individual whom I believe understands that the proper role of a judge is to apply the law and not invent it. I am confident he will be an outstanding member of the Supreme Court who will be a responsible and influential voice for years to come.”

Frmr Sen. Rick Santorum (R-PA): “I can think of no one more qualified and worthy to fulfill the role of Chief Justice of the Supreme Court than Judge Roberts.”

Sen. Chuck Grassley (R-IA): “I believe that at his hearing last week, Judge Roberts demonstrated that he will be fair and open-minded, and will approach cases without bias and without a personal agenda. This is the kind of judge that everyone – both liberals and conservatives alike – wants on the bench.”

Tell Congress that you stand with Obamacare by adding your name here.

The Supreme Court has upheld the individual mandate in Obamacare, paving the way for full implementation of the law in the states and ensuring that millions of uninsured Americans haves access to affordable coverage. The court upheld the provision as a tax, but found that it does violate the Commerce Clause.

The Medicaid expansion is limited, but not invalidated, the court found. In short, it decided that if a state does not expand the Medicaid program, as required by the law, the federal government cannot withhold Medicaid funds.

In short, “the entire ACA is upheld, with the exception that the federal government’s power to terminate states’ Medicaid funds is narrowly read.”

Chief Justice John Roberts joined Justices Sonya Sotomayor, Stephen Breyer, Ruth Bader Ginsburg, and Elena Kagan in the 5 to 4 decision. Justice Anthony Kennedy — who was considered a swing vote on in the case — sided with the conservatives.