Senate Democrats held a high-stakes test vote this evening for financial regulatory reform. While it was merely the procedural motion on cloture to begin formal debate, Democrats hoped to prove that they had the required 60 votes to move forward with reform legislation. The measure, which would have needed every Democrat and one Republican to pass, failed with no Republicans supporting and Democrat Ben Nelson voting against. Here are the first reactions.

• Why This Is Bad for Democrats  Because, explains liberal blog Open Left, it will change the story from one about Republicans working on behalf of Wall Street to one about Democratic in-fighting. "So far Ben Nelson's 'no' vote seems to be the headline. Dems need 'GOP blocks Wall Street bill' not 'Dem blocks bill.'"

• Liberals Fume at Nelson  Why did Nelson vote no when the measure would have failed even without his opposition? The New Republic's Jonathan Chait has a theory: "Ben Nelson votes to filibuster financial regulation, saying, 'this legislation will adversely impact Main Street.' And by 'Main Street,' he means 'Warren Buffett.'" Karoli writes, "In true form, Ben Nelson has voted with his Republican friends and Wall Street benefactors to filibuster financial reform. He didn't even have to do it." Doug Weathers scoffs, "Why does Ben Nelson even caucus with Democrats? He won't support even debating the Democratic agenda!" Slate's Chris Beam adds, "Ben Nelson is your new cold sore."

• Why He Might Have Voted No  The Washington Independent's Annie Lowrey suggests, "my guess is that Nelson knew the motion would not pass, having failed to garner Sen. Olympia Snowe’s (R-Maine) vote earlier today, and decided not to vote for it at that point." Matthew Yglesias thinks Nelson was acting on behalf of Warren Buffett, who has lobbied the Senate for a special concession for his company, Berkshire Hathaway.
  

• How Will Tea Parties React?  Blogger Kombiz Lavasany scoffs, "And the Republican party successfully filibustered a bill on behalf of the big Wall St. banks.. how you doing tea parties?"

• Republican Obstructionism Continues  Liberal blogger Jesse Taylor fumes, "So, Republicans can't vote for popular bills, can't vote for divisive bills and can't vote for unpopular bills. Why are they there?"

• End of Scott Brown?  Liberal blogger E.D. Kain predicts doom for the newly minted Republican Senator from Massachusetts. "You mean 'single-term Senator Scott Brown votes to filibuster [financial regulatory reform].' This isn't [health care reform] anymore, and this probably won't fly in MA."

• What's Next?  The American Prospect's Tim Fernholz predicts, "Now comes more politics. Harry Reid switched his vote so that Democrats can hold another cloture vote down the line. And get ready for a tough message from the Democrats, accusing Republicans of standing alongside Wall Street to hamstring reform."

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