Bad news: Jay Carney doesn't like questions about Obama's budget

To cleanse the palate, a simple question: Since only 51 votes are needed to pass a budget in the Senate and there are 53 Democratic and left-leaning independent senators, why doesn’t smilin’ Harry Reid ram through O’s latest spending blowout? The White House gets awfully fidgety when the media presses them on this, to the point where even former OMB director Jack Lew was forced to play dumb about how many votes are needed for Democrats to pass this thing. Any theories? Any hypotheses for why The One might be nervous about vulnerable red-state Democrats like Claire McCaskill and Jon Tester taking a vote on a budget that calls for another $1.3 trillion deficit this year and a cool $901 billion deficit next year? Leave your informed speculation in the comments.