Our guest blogger is Adam Jentleson, the Communications and Outreach Director for the Hyde Park Project at the Center for American Progress Action Fund.

The centerpiece of John McCain’s health care plan is a tax credit worth $2,500 for individuals. By coincidence, in her speech at the RNC two weeks ago, Gov. Sarah Palin wore a jacket designed by Valentino Garavani that cost $2,500.

Admittedly, McCain’s health care tax credit is worth more than most jackets. The problem is that it’s worth far less than the cost of health care for most Americans.

Individuals paid an average of $4,400 for health care in 2007 – nearly twice the value of McCain’s credit. For families, McCain’s credit is $5,000 – which covers less than half of the $12,000 the average American family paid for health care in 2007.

And unlike Gov. Palin’s jacket, McCain’s credits are not tailored. They are one-size-fits-all. So if you’re healthy, you should be in good shape. But if you are sick, have a pre-existing condition, or endure a medical emergency, once you exceed the value of the credit you are on your own.

Which is why many health care experts agree than McCain’s health care plan boils down to this: don’t get sick.

Yesterday, an independent study published in Health Affairs concluded that Sen. John McCain’s (R-AZ) health care plan would undermine employer-based health coverage, insure just one-million more Americans, and increase costs across the board.

And while some employers would still offer health insurance, McCain’s prescription could allow large firms to discriminate between workers and provide different benefits to high-and low wage employees.

Currently, “to qualify for the tax subsidy” — which shields health benefits from taxes — “employers must abide by IRS nondiscrimination rules, which require firms to provide similar benefits to high-and-low wage employees.”

In short, “all benefits provided for participants who are HCEs [highly compensated employee] are also available to all other participants. All benefits for dependents of HCEs must also be available for the dependents of all other employees.”

But McCain’s health care plan may undermine this protection. By eliminating the current tax exclusion for employer-sponsored coverage, McCain would erode the tax incentive that encourages large employers to provide their workers with identical benefit packages.

With income inequality at an all time high, McCain’s plan could create a new ‘health care gap.’