As congressional Republicans continue to hold the economy hostage to their ideological whims during the ongoing debt ceiling negotiations, one GOP senator betrayed just how weak his understanding of the situation — and basic arithmetic — is. Sen. John Cornyn (R-TX) tweeted and posted on his Facebook page this message: “Raising $2 trillion in taxes in exchange for $2 trillion in budget cuts nets zero in terms of the size of government, unless taxes are reserved for debt reduction.” Cornyn doesn’t seem to understand that raising taxes would add to, not subtract from, the money saved by making cuts, further reducing the deficit. But by Cornyn’s logic, $2 trillion in cuts + $2 trillion in tax increases = $0. The last part of his message — “unless taxes are reserved for debt reduction” — is equally nonsensical, as the money collected from taxes isn’t separated into “pools” for different purposes. Revenue is revenue, but Cornyn is trying to suggest, as he has before, that President Obama is trying to raise taxes for the heck of it, not to pay down the deficit.