By DAVID M. HERSZENHORN
WASHINGTON — Senate Republicans on Thursday blocked an effort by Democrats to start debate on legislation to tighten regulation of the nation’s financial system, and the two sides traded bitter accusations about who was standing in the way of a bipartisan agreement.
The majority leader, Harry Reid of Nevada, asked Republicans to agree to begin debating the measure, which would impose a sweeping regulatory framework on Wall Street and big financial institutions. But the Republican leader, Senator Mitch McConnell of Kentucky, objected, saying Democrats were pre-empting negotiations to reach a deal.
In response, Mr. Reid said he would call the first procedural vote on Monday in an effort to stop the Republican filibuster. That vote could test Republican resolve to oppose the measure in an election year, amid public dismay over big Wall Street profits and bonuses even as unemployment remains high.