Once upon a time, when newly elected members of the House of Representatives arrived in Washington, they were expected to be seen and not heard. They found mentors among more experienced members of Congress, went quietly to work on issues important to their home districts — highway construction, defense contracts — and concentrated on getting re-elected for a second term.

No longer. The giant 87-member class of Republican freshmen that arrived this year isn’t behaving like earlier generations. Seventy-six of them won the endorsements of “tea party” groups; they believe they have a mandate to cut federal spending, shrink the federal government and repeal President Obama’s health care law. And they have no intention of waiting.

“The reason I ran is that I recognized that our country was in trouble,” Rep. Kristi Noem, R-S.D., one of the leaders of the freshman class, told me last week. “We were spending money we don’t have. We have to stop that.”

In their first month on the job, many of the freshmen joined in a series of small rebellions against their own leadership. When Speaker John A. Boehner, R-Ohio, proposed to cut spending for the rest of the current year by about $31 billion, the rebels demanded cuts that would add up to $100 billion. And in an implicit rebuke to Boehner himself, they eliminated spending on a jet fighter engine that was being built in the speaker’s Ohio district.

For a few days there, the House floor looked out of control.

But Boehner and his lieutenants responded. They turned their orientation program for the freshmen into “listening sessions,” to give the new members a chance to vent and offer suggestions directly to their leaders.

“It gave them an ability to speak,” said Rep. Kevin McCarthy, R-Calif., the Republican whip, who conducted many of the intergenerational meetings. As a result of the listening sessions, he told Boehner: “Your initial number is not going to go.”

In the end, the House voted for a $61 billion cut, the Republi- cans’ opening bid in negotiations with the Democratic-led Senate.

Now McCarthy and Rep. Paul D. Ryan, R-Wis., chairman of the House Budget Committee, are using more listening sessions to prepare for their next big decisions: what to do if the Senate, as expected, responds with a proposal for, say, $40 billion in cuts. And what to do when the time comes to raise the federal debt ceiling — the amount of money the Treasury is allowed to borrow to keep the government running.

If the tea party freshmen and other hard-line conservatives dig in their heels on the spending bill, the result could be a shutdown of much of the federal government, a tactic that backfired on Republicans when then-Speaker Newt Gingrich tried it in 1995. And if they balk at raising the debt ceiling, the result could be chaos in the financial markets, another problem the GOP leadership doesn’t want to be blamed for. Last year, Boehner said the debt-ceiling vote would be the freshman members’ first “adult moment,” a demeaning phrase he has been careful not to repeat.

So McCarthy and Ryan have been holding hours of meetings with the freshmen, showing them Ryan’s collection of PowerPoint slides to help bring them up to speed on the hard facts of the federal budget, and to nudge them toward compromise

The graph that grabs everyone’s attention is one that shows federal debt held by the public as a dramatic wedge of red ink that swells from less than 100 percent of gross domestic product now to a staggering 700 percent by about 2075. It’s a deliberate scare tactic, based on what would happen if nobody took any action at all to curb the deficit — in other words, it’s neither fair nor realistic. Both parties have proposed spending cuts, and Obama has proposed increasing taxes on upper-income taxpayers. But GOP members love the graph (it’s online at budget.house.gov, and many have taken the slide home to show at town meetings.

Still, Ryan’s slides also show that, no matter how high the cuts in domestic programs, the red ink will persist.

“You take discretionary nondefense (spending) out, you still don’t balance the budget,” McCarthy said, pointing at one of Ryan’s pie charts. The current spending bill, he said, is just a small “bite of the apple”; next year’s budget is “the entree.”

And there’s another slide in Ryan’s presentation that the Republicans haven’t faced up to yet. That’s the one that shows that the biggest driver of future deficit growth is Medicare spending, unless it’s brought under control.

When I asked members of the freshman class what they planned to do about Medicare, they basically punted.

“We’ve got to come up with a more efficient delivery system for health care,” said Rep. Blake Farenthold, R-Texas.

So did McCarthy. “You have to do something on Medicare,” he agreed. But he said he wants to have a long conversation with voters, most of whom staunchly oppose cuts in Medicare spending, before signing on to any particular solution.

“I like the idea of talking to the American public first about all the problems,” he said.

On the easy decisions — short-term spending and the debt ceiling — the freshmen are gradually being housebroken. Many of them now sound open to compromises, as long as they include sizable spending cuts. And they’ve largely accepted Boehner’s argument that they shouldn’t block an increase in the nation’s borrowing power. “That debt ceiling vote isn’t going to define us,” Noem said.

But on the harder issues of fixing the federal budget for the long run — which means, first of all, Medicare — they’re still a long way from their moment of truth.

Doyle McManus is a columnist for the Los Angeles Times.