It has become glaringly obvious over the past couple months that President Obama wants to nominate Larry Summers to become the next chair of the Federal Reserve. According to CNBC’s John Harwood, Obama feels he “owes” Summers for his willingness to serve the country during the first-term response to the Great Recession.

But might a Summers nomination be D.O.A. in the Senate? Outside groups have already plotted behind the scenes to stop Summers; his allies in the White House will doubtlessly respond with a campaign of their own. But Summers’ biggest obstacle is simple math: He has to be able to count to 12.

Twelve is the number of votes Summers would need to advance out of the Senate Banking Committee, which poses the biggest challenge to confirmation. Generally speaking, a presidential appointee cannot advance to the executive calendar and a final Senate vote without a positive recommendation from the committee of jurisdiction. The last time a committee nearly derailed a high-profile nominee domination was John Bolton’s appointment as U.N. Ambassador in 2005. Eventually, Bolton’s nomination went to the full Senate under highly unusual circumstances. Republican Senators George Voinovich and Lincoln Chafee did not support Bolton, but they agreed not to block the nomination if the committee advanced Bolton to the floor with "no endorsement" instead of a recommendation.

It’s unclear whether anti-Summers Democrats will give the same leeway. The Wall Street Journal, citing unnamed Senate aides, suggested that three Banking Committee Democrats would oppose Summers: Sherrod Brown, Jeff Merkley and Elizabeth Warren. The three have created an ad hoc pro-financial reform coalition inside the committee, dedicated to tighter regulations and more vigorous policing of Wall Street. Warren told me last month that she greatly respected Brown and Merkley, and saw them as forming “a core of people really engaged with the issues.”

Sherrod Brown has already gone public with his opposition to Summers. He circulated the letter urging Obama to choose current Fed Vice Chair Janet Yellen for the position. Neither Merkley nor Warren have publicly stated they would oppose Summers in committee, and the Journal report didn’t come from either of their offices. But Merkley has been quite critical of a potential Summers choice from the moment it was floated. “If you nominate someone who is a life-committed deregulator to be in a regulatory position … why is this person appropriate?” he asked Bloomberg in late July.