WASHINGTON -- A conservative pro-gun firebrand, a senator once called "crown prince of the Tea Party movement" and a liberal former Pennsylvania governor seem like an odd group for a coffee klatch, but the three got together Thursday morning with the same thing on their mind: the national debt.

U.S. Sens. Ted Cruz, R-Texas, and Marco Rubio, R-Fla., and Ed Rendell addressed 100 veterans at a breakfast forum sponsored by Concerned Veterans for America.

In separate speeches, each said the nation is headed for trouble if leaders don't reduce the debt. But that's where the commonality ended.

For Mr. Rubio, the solution involves lower taxes, less regulation and more reliance on free enterprise. Mr. Cruz advocated for a return to Reagan-era restraint in government spending and lower taxes.

That view of history was too rosy for Mr. Rendell, a Democrat.

"This is not intended to be a debate, nor should it be ... but I do want to correct the record," he said. "President Reagan did cut taxes, but he raised taxes 11 times and he increased government spending -- significantly increased government spending -- in his first two years he took over in an effort to stimulate the economy. Sound familiar?"

Concerned Veterans for America CEO Pete Hegseth said his organization held the forum as part of its mission to encourage veterans to get involved in public policy. "We talk about thinking outside the Kevlar," he said. "We're not trying to be a think tank. We want to be a group that gets behind good ideas."

Members and others in the audience of 100 heard plenty of ideas Thursday along with a few political barbs.

"I'm trying to sort out the politics of it. There's always politics," said Stewart Reuter, a Navy veteran who lives in Washington, D.C. "There is some hope for bipartisanship, I suppose. There has to be, to avoid disaster."

Brooke Lowry, 25, a D.C. mortgage lender who grew up in Florida, has been a longtime supporter of Mr. Rubio, but was glad to hear from Mr. Cruz as well as Mr. Rendell. "Marco Rubio has a very structured, conservative outlook that most conservatives would agree with," she said. "But Rendell talked about reeling in some government programs that currently exist, so there's movement there" from Democrats who tend to favor more spending on entitlements, she said.

She was referring to Mr. Rendell's advocacy of a plan to use a chained consumer price index to calculate Social Security payments, which would reduce payments. It's a plan that has conservative support, but faces opposition from groups including the American Association of Retired People.

"Chained CPI will slow the growth of benefits. That's the way we ensure that Social Security and Medicare are going to be there," Mr. Rendell said.

He asked fellow Democrats to get on board. Republicans need to change their thinking, too, he said. "Republicans have to get over this idea that it's evil to raise revenue. It isn't evil," said Mr. Rendell, national co-chairman of Campaign to Fix the Debt, a nonpartisan group led by political powerbrokers advocating for a mix of budget cuts and revenue increases.

He said leaders in Washington have to address the debt aggressively. "We need to do something big. We can't nibble at the edges," he said. "It's going to require courage and it's going to require guts."

Democrats have to be willing to reduce entitlements and Republicans have to be willing to increase revenue, he said.

The revenue could come from several different sources. Some options, he said, include raising taxes on millionaires, cutting oil and gas subsidies, and capping mortgage deductions.

Mr. Rubio, meanwhile, said the solution is smaller government, not more revenue.

He said the philosophical disagreements can't be bridged.

"You cannot have limited government and big government at the same time, and that's the problem we're facing," he said. "Because of that deep philosophical divide we cannot pass a budget."

The Campaign to Fix the Debt is trying to find common ground, said T.J. Rooney, the group's Pennsylvania co-chairman.

"There are people who care more about the debt than about partisan politics," said Mr. Rooney, former state Democratic Party chairman, in a telephone interview.

Mr. Rooney and Fix the Debt leaders from other states plan to converge on Washington next week to encourage members of Congress to take action before the nation's $17 trillion debt grows.