The Senate tax bill would raise only $458 billion in increased revenue from economic growth over the next decade and will increase the deficit by more than $1 trillion, according to the Joint Committee on Taxation. It would increase GDP by .8 percent relative to current law over 10 years.

Why this matters: Republicans, who conventionally are against adding to the federal debt, have been insisting their tax bill pays for itself, and thus they are fine with voting for it. The official government analyst says it doesn't, but don't expect that to change any GOP votes that weren't already in question.