“It will be defeated, they know that, the American people should understand that clearly,” Reid said.
Fifty-three members of the Senate Democratic Conference issued a letter to Boehner on Wednesday night in which they promised to vote down his debt-ceiling plan if it reaches the Senate.
The plan cannot pass the upper chamber without Democratic support.
The latest version of Boehner’s plan would cut $917 billion in spending while adding $900 billion to the current $14.3 trillion debt limit.
It also would create a commission charged with finding another $1.8 trillion in savings by Nov. 23, and would require a second debt-limit increase before the 2012 elections.
A vote on Boehner’s plan is scheduled for late Thursday afternoon in the House.