For months, mayors across the country have discussed the importance of preserving the Community Development Block Grant (CDBG) program. But they haven't done it the way they did today.

At a media event today in the swanky St. Regis Hotel in Washington, D.C., dozens of mayors detailed how proposed cuts to the program would affect their communities. Mayors are seeking to block Republicans in the House from eviscerating the grant program that provides $4 billion annually for programs such as affordable housing and job training to low- and moderate-income residents.

The mayors demonstrated a distinct shift in tone from previous discussions on CDBG cuts, opting for an angrier and more defiant approach than they have in the past. The move comes after the Republican-controlled House passed a continuing resolution earlier this month that cuts CDBG by 62.5 percent to $1.5 billion.

In previous discussions, the mayors have spoken in measured tones, higlighting the impact of the program and the need to educate lawmakers about its role in the communities.

Today, Philadelphia Mayor Michael Nutter compared the proposed GOP cuts to a bazooka pointed at cities. He and others called such dramatic cuts "un-American."

"There are cuts, and there's insanity, and this is insanity," Nutter said.

President Obama has also proposed cutting CDBG in his 2012 budget, but by only 7.5 percent. While mayors aren't happy with that decision, it's more palatable than the House's plan. Mayors say they're focusing on the current budget battle before they address a larger threat. The Republican Study Committee, which represents more than half of the Republicans in the House, has proposed eliminating CDBG entirely in 2012.

Davenport, Iowa, Mayor Bill Gluba raised his voice to a shout as he vehemently defended the program at today's press conference organized by the U.S. Conference of Mayors. He said if the mayors' words go unheeded, there will be protests by people who have benefited from CDBG programs.

"(W)e're going to bring them to Washington, and we're going to have a major march or meeting in the halls of Congress with the leadership of Congress," Gluba said. "We are not going to let them destroy this fundamental, basic program that has served this country for over 30 years."

Both Democratic and Republican mayors expressed frustration with members of the Republican-controlled House, who they say are inexperienced and likely don't understand what CDBG does. For their part, Republican lawmakers have said that isn't the case. Those who oppose the program say it is wasteful and cite a 2006 inspector general report that found fraud, misuse of funds and a lack of oversight in the program. President Obama's own budget says the program's lack of clear focus makes it difficult to evaluate.

The mayors, however, say that the program's flexibility is an asset, allowing them to tailor it to the challenges facing each community. They also insist the program is transparent, noting reams of paperwork and multiple boards and commissions convened at the local level to ensure the proper use of CDBG funds. Newton, Mass., Mayor Setti Warren, chair of the mayors' community development committee, says the program has created or retained 250,000 jobs in the last six years.

Mick Cornett, mayor of Oklahoma City and head of the association representing Republican mayors, criticized those who have also justified the cut in the name of balancing the budget. "It's a little bit lame for us to hear that they've got 'tough choices' to make," Cornett said of federal lawmakers. "Let me tell you, you be mayor for a day, and I'll tell you about some tough choices."

Cutting CDBG won't eliminate the problems the program helps address, said Mesa, Ariz., Mayor Scott Smith. Instead, it will simply shift the burden of financing those services to cities, which are already facing shortfalls and must still find a way to balance their budgets, unlike Congress. "This is merely a cost shift," Smith said. "This is a shifting of responsibility."

Several mayors said that they're relying on the Senate to act as a "backstop" to protect against the deep cuts passed by the House.

But Burnsville, Minn., Mayor Elizabeth Kautz, president of the U.S. Conference of Mayors, declined to say whether mayors would be willing to see a government shutdown if it meant saving the program. The current spending bill expires March 4, and the government would shut down unless the House and Senate agree to a spending bill before then.

The House has passed a spending bill containing $61 billion in cuts covering the remainder of the fiscal year, which ends Sept. 30. The Senate, controlled by Democrats, is strongly opposed to the Republican spending bill and will almost certainly not approve that legislation.