Washington (CNN) - A leading grassroots conservative organization and an influential fiscal conservative group say they're making final pushes Thursday to try and defeat House Speaker John Boehner's plan to reduce the nation's debt.
FreedomWorks says it's reaching out to its conservative allies in the House, including lawmakers and their staff, in the hours before the chamber is expected to hold a pivotal vote on the Republican Speaker's proposal.
"We've been spending time sending last minute emails, making phone calls and alerting our members and tea party leaders in some of these districts about our opposition to this plan. This morning we plan to stop by as many House offices as possible to deliver our message in person to staff as the debate is occurring on the House floor," Brendan Steinhauser tells CNN.
"Our goal is to peel off enough Republican votes in the House to stop this bad debt plan, which doesn't meet the criteria of cut, cap and balance, and won't fix our overall debt problem."
Steinhauser, who is not related to this reporter, is director of federal and state campaigns for FreedomWorks, a nonprofit conservative organization based in the nation's capital that helps train volunteer activists and has provided much of the organization behind the tea party movement. The group also supports conservative candidates in Republican primary and general election contests.
Boehner is trying to stomp dissent within his party. Two GOP sources said Wednesday that the Speaker called on fellow Republicans to "get your ass in line."
The House vote will be a major test for whether the GOP caucus can push through the Boehner measure in the face of an expected unified Democratic opposition. Republicans hold 240 of the 433 House seats (two seats are currently vacant), and if everyone votes, 217 votes would be need to pass the Speaker's plan.
The nonpartisan Congressional Budget Office says revisions to Boehner's plan would bring a total of $917 billion in savings over 10 years, an increase of about $65 billion over the initial version. With the revisions, Boehner's proposal - which calls for an immediate $900 billion increase in the debt ceiling - now meets his pledge to match any debt ceiling hike with dollar-for-dollar spending cuts.
Senate Democrats said in a letter Wednesday that the Republican plan has no chance of passing the Senate. For their part, top Republicans called the Senate Democratic plan a nonstarter.
Steinhauser tells CNN that "some of the folks we are trying turn into NO votes" include: Representatives Allen West of Florida, Marsha Blackburn of Tennessee, Bill Johnson of Ohio, Blake Farenthold of Texas, Doug Lamborn of Colorado, Mike Pence of Indiana, Austin Scott of Georgia, Bill Flores of Texas, Jack Kingston of Georgia, Scott Garrett of New Jersey, Joe Barton of Texas, and Kevin Brady of Texas.
He listed 18 House Republicans as firmly committed to voting against the Speaker's plan. They are: Representatives Todd Akin of Missouri, Michele Bachmann of Minnesota, Paul Broun of Georgia, Jason Chaffetz of Utah, Jeff Duncan of South Carolina, Jeff Flake of Arizona, Chuck Fleischmann of Tennessee, Phil Gingrey of Georgia, Louie Gohmert of Texas, Tom Graves of Georgia, Tim Huelskamp of Kansas, Jim Jordan of Ohio, Connie Mack of Florida, Mick Mulvaney of South Carolina; Ron Paul of Texas, Dennis Ross of Florida, Steve Southerland of Florida and Joe Walsh of Illinois.
FreedomWorks isn't the only conservative powerplayer in the nation's capitol that's working to defeat the Boehner plan. The fiscal-conservative Club for Growth is also urging House Republicans to vote against the re-worked proposal by the Speaker.
"The increase in the debt limit is immediate and real, but most of the spending cuts are only promised and stretched out over ten years. History has shown that future spending cuts rarely materialize. Nothing binds a future Congress from erasing them," says an email Thursday morning from the group which was sent to congressional offices.
If Congress fails to raise the current $14.3 trillion debt limit by August 2, the federal government could come up short in paying its bills, and Americans could face rising interest rates and a declining dollar, among other problems.
- CNN's Alan Silverleib and Tom Cohen contributed to this story.