House Democratic leaders on Wednesday called for a clean vote on raising the debt ceiling to prevent a government default. 

House Minority Leader Nancy Pelosi (D-Calif.), Minority Whip Steny Hoyer (D-Md.), Assistant Leader James Clyburn (D-S.C.), Democratic Caucus Chairman John Larson (D-Conn.) and Rep. Xavier Becerra (D-Calif.), the caucus vice chairman, are all pushing legislation to increase the debt ceiling by $2.4 trillion — enough to see government spending through 2012.

The bill, sponsored by Rep. Peter Welch (D-Vt.), contains none of the deficit-reduction provisions Republicans are demanding as part of a larger debt-ceiling package.  

In a letter urging support from House Democrats, the leaders warned that the debt-limit issue might not be resolved by the Treasury's default deadline.

"We are concerned that these negotiations may not conclude by August 2," the letter states. "America is now on the doorstep of default. We cannot allow the failure of these negotiations to become America’s failure to pay its bills."

The Welch bill has attracted 100 Democratic cosponsors, and the lawmaker's office said it expects that number to grow.

The renewed push for a clean bill arrived as House Republicans were releasing the details of a tweaked version of their own debt-limit proposal. The amended bill would cut deficit spending by $917 billion over the next decade — $22 billion of that coming next year.

The new figures are designed to entice some conservative Republicans who had balked at the scope of the cuts in the earlier version of the bill.