The president's $447 billion package will almost certainly fail in the Senate Tuesday night -- and members of his own party could help stall it

From left to right: Democratic Sens. Joe Manchin (W.Va.), Ben Nelson (Neb.), and Jon Tester (Mont.)

The Senate will vote Tuesday evening on President Obama's $447 jobs bill, which he's been promoting in appearances around the country. The bill will almost certainly fail.

Democrats control 53 Senate seats, and they'll need 60 votes to clear a procedural hurdle and move toward final consideration. With Republicans pledging to block the plan, Tuesday's vote will be a "test vote," measuring how much support Obama's bill enjoys.

A few Democrats will likely vote against it. The question, now, is how many.

In an interview with MSNBC's Chuck Todd on Tuesday morning, Sen. Chuck Schumer (D-N.Y.) hinted that some Democrats will probably vote no.

"We're likely to lose two, three, four Democrats," Senate Majority Whip Dick Durbin (D-Ill.) told Chicago's WTTW TV on Monday. When asked on Tuesday how many Democrats will support the president's plan, Durbin spokesman Max Gleischman said that "the vast majority" will back it.

A few Democratic "no" votes could look bad for the president, as Republicans have sought to highlight a lack of support for the package in Obama's own party. But Democratic leaders almost always lose a few votes from swing-state senators, and if Obama's bill fails, it will be almost exclusively because Republicans oppose it.