By Erik Wasson

President Obama came under new pressure Friday to broaden talks about government spending to include tax and entitlement reform.

Sixty-four senators — 32 Democrats and 32 Republicans — called for the expanded talks in a letter to Obama.

The letter was circulated by Sens. Mike Johanns (R-Neb.) and Michael Bennet (D-Colo.), who were able to get a supermajority of the Senate within 24 hours. It urges Obama to "engage in a broader discussion about a comprehensive deficit-reduction package." 

"Specifically, we hope that the discussion will include discretionary spending cuts, entitlement changes and tax reform," the letter states.

It endorses the report late last year from Obama's fiscal commission as a basis for the conversation.

"As you know, a bipartisan group of senators has been working to craft a comprehensive deficit reduction package based upon the recommendations of the Fiscal Commission," the letter states. "While we may not agree with every aspect of the Commission’s recommendations, we believe that its work represents an important foundation to achieve meaningful progress on our debt."

The letter does not specify what entitlements and tax reforms should be included in the talks.

“We need the White House to be engaged,” Johanns said in a press call explaining the letter. “There is no question that tackling tax reform and entitlements is tough … We won’t have any chance unless the president joins with us in the good-faith effort.

“The ball is very clearly in the president’s court,” Johanns said.

“We want to work toward a comprehensive plan,” Bennet said. “This is about keeping the conversations going, keeping it alive.”

Discussions in Washington on spending have focused on the current fiscal year, with Democrats and Republicans battling over about $50 billion in domestic discretionary spending.

Separately, six senators from both parties have been working to put the bipartisan recommendations of Obama's fiscal commission into legislation. The debt commission included tax and entitlement reforms in its recommendations.

The group — Sens. Dick Durbin (D-Ill.), Kent Conrad (D-N.D.), Tom Coburn (R-Okla.), Mike Crapo (R-Idaho), Mark Warner (D-Va.) and Saxby Chambliss (R-Ga.) — met again Thursday night to continue their negotiations. The Republicans in the group are under heavy pressure from outside groups not to endorse reforms that increase taxes, while the Democrats are being lobbied not to include Social Security reform.

Senate Majority Leader Harry Reid (D-Nev.) said this week that he would be open to tackling Social Security in 20 years, a statement that House Budget Committee Chairman Paul Ryan (R-Wis.) described as mind-boggling.

Speaker John Boehner (R-Ohio) has offered to give the president political cover if he takes up entitlement reform. Obama did not include entitlement reforms in his budget proposal for the next fiscal year.

Reid and Senate Minority Leader Mitch McConnell (R-Ky.) did not sign the letter and were not asked to, according to Johanns, who said this was in keeping with Senate tradition.

Senate Majority Whip Dick Durbin (D-Ill.) has signed the letter, as has Senate Minority Conference Chairman Lamar Alexander (R-Tenn.).

Johanns said this is the best year to tackle a comprehensive plan since next year is an election year. Bennet said that simply talking about 2011 funding is not sufficient.

Here is the full text of the letter to Obama, followed by the names of the senators signing the letter:

Dear President Obama:

As the Administration continues to work with Congressional leadership regarding our current budget situation, we write to inform you that we believe comprehensive deficit reduction measures are imperative and to ask you to support a broad approach to solving the problem.

As you know, a bipartisan group of Senators has been working to craft a comprehensive deficit reduction package based upon the recommendations of the Fiscal Commission.  While we may not agree with every aspect of the Commission’s recommendations, we believe that its work represents an important foundation to achieve meaningful progress on our debt.  The Commission’s work also underscored the scope and breadth of our nation’s long-term fiscal challenges. 

Beyond FY2011 funding decisions, we urge you to engage in a broader discussion about a comprehensive deficit reduction package.  Specifically, we hope that the discussion will include discretionary spending cuts, entitlement changes and tax reform.

By approaching these negotiations comprehensively, with a strong signal of support from you, we believe that we can achieve consensus on these important fiscal issues.  This would send a powerful message to Americans that Washington can work together to tackle this critical issue.

Thank you for your attention to this matter.

Republicans signing the letter:

Sens. Lamar Alexander (Tenn.),  Kelly Ayotte (N.H.), John Barrasso (Wy.), Roy Blunt (Mo.), John Boozman (Ark.), Scott Brown (Mass.), Richard Burr (N.C.), Saxby Chambliss (Ga.), Dan Coats (Ind.), Tom Coburn (Okla.), Thad Cochran (R-Miss.), Bob Corker (Tenn.), John Cornyn (Tex.) Mike Crapo (Idaho), Mike Enzi (Wy.), Lindsay Graham (R-SC) John Hoeven (R-ND), Kay Bailey Hutchison (R-TX), Jim Inhofe (R-OK), Johnny Isakson (R-GA), Ron Johnson (R-WI), Mark Kirk (R-IL), Mike Lee (R-UT),  Jerry Moran (R-KS), Lisa Murkowski (R-AK), Rob Portman (R-OH),  James Risch (R-ID), Pat Roberts (R-KS), Richard Shelby (R-AL), John Thune (R-SD) and Roger Wicker (R-MS).

Democrats signing the letter:

John Kerry (D-MA), Amy Klobuchar (D-MN), Ron Wyden (D-OR), Jeanne Shaheen (D-NH), Joseph Lieberman (ID-CT), Kay Hagan (D-NC), Mark Begich (D-AK),  Thomas Carper (D-DE), Mark Udall (D- CO), Mark Pryor (D-AR), Dianne Feinstein (D-CA), Jon Tester (D-MT), Christopher Coons (D-DE), Ben Nelson (D-NE), Claire McCaskill (D-MO), Bill Nelson (D-FL), Joe Manchin (D-WV), Benjamin Cardin (D-MD), Al Franken (D-MN), Mary Landrieu (D-LA) , Kent Conrad (D-ND) , Mark Warner (D-VA), Richard Durbin (D-IL), Tom Harkin (D-IA), Herb Kohl (D-WI), Patty Murray (D-WA), Debbie Stabenow (D-MI), Jeff Bingaman (D-NM), Richard Blumenthal (D-CT), Tom Udall (D-NM) and Sherrod Brown (D-OH).