While Democrats and Republicans talk shop in partisan lunches throughout the week, Sens. Mark Kirk and Joe Manchin look forward to their weekly lunch date.

In a throwback to a more bipartisan era, the Illinois Republican and West Virginia Democrat have, for more than two months, met for a little cross-party chitchat. They’ve invited colleagues to join them. So far, few have.

It’s an oft-told story, but the Kirk-Manchin lunches are a reminder that Congress is no longer the bipartisan place it used to be. Aside from a few basketball games in Congressional gyms and the weekly bipartisan prayer breakfasts, Members have few opportunities to strike up friendships across the aisle.

The two freshmen started the lunch meetings in March for this very reason. They began meeting in the often-deserted Senate Room 113, a small dining area which staff sets daily with white tablecloths, glasses and silverware.

“It was like a museum piece: Set up every day for Members that never showed up,” Kirk said. “My main man Manchin and I have adopted that room on Thursdays.”

In the months since, they’ve extended personal invites to other Senators and sent reminder emails, but they can count on two hands the Members who have joined their bipartisan lunches.

Sometimes they eat alone.

Former Rep. Bill Frenzel (R-Minn.), who served in the 1970s and 1980s, said Democrats and Republicans used to bond at the card table, in the gym, at the bar and on airplanes and buses.

In his day, paddle ball and basketball were popular. Members played on a daily basis, dividing teams by state, region, collegiate or party lines.

And when leadership called votes in the late afternoon, Frenzel remembers sweaty Members entering the chamber in sweat socks and tennis shoes to vote.

Committee members, he said, also traveled around the world together frequently to learn firsthand about policy issues. He joined Republicans and Democrats on trips to Brussels, Geneva and Japan at least once a year and fondly recalls plowing across Eastern Europe in an overcrowded bus with subcommittee colleagues and their wives.

Rep. John Dingell (D-Mich.), who was first elected in 1955, used to fish and hunt geese with former Reps. John Saylor (R-Pa.) and Edwin Forsythe (R-N.J.). He also vacationed in Colorado, Montana and Texas with a half-dozen Members of both parties.

Former Rep. Connie Morella (R-Md.) said 60 to 100 Members used to take retreats together in nonelection years when she was in office.

“They’d put us on a bus together, and we’d get away for a long weekend,” Morella said. “They’d invite speakers to talk to us about working together, and we’d do fun activities, have a nice dinner or play games in the game room.”

Morella said such friendships were critical for legislating.

“In those days, establishing those relationships was necessary because you knew you couldn’t get anything done if you couldn’t get a Member of the other party to sign on,” she added.

Some experts attribute the loss of cross-party activities to increasingly nasty politics, but just as many blame the lack of bipartisan activities on constituent demands and time constraints. Kirk argues it is a “direct result of President [Jimmy] Carter deregulating the airline industry” — which led to lower airfares.

Former Defense Secretary Donald Rumsfeld, who represented Illinois in the House in the 1960s, told Kirk that a flight from Washington to Chicago back then cost $1,500 while Members only made $30,000. It didn’t make sense to visit home while Congress was in session.

With today’s cheaper air fares, Members almost can’t afford not to go home.

“Not only do vulnerable House Members leave immediately for home, but the culture says that you’re almost a bad Member of Congress if you’re not on a plane within one hour of the last vote,” Kirk said.

That notion “ended the social fabric of the Congress,” he said, leaving little to no time for bonding.

Norm Ornstein, Congressional expert at the American Enterprise Institute and a Roll Call contributing writer, said Members’ family living arrangements have also contributed.

“It used to be the case that Members would move their families to Washington, and if they were here in Washington, they’d spend weekends together,” he said.

They also dined frequently with Members of the opposite party frequently. Former Sen. Fritz Hollings’ (D-S.C.) wife used to organize dinner parties for 10 to 15 Congressional couples, recalls Sen. Lamar Alexander (R-Tenn.). Each week, a different couple would host. But the tradition eventually died when  Senate schedules grew too hectic for regular get-togethers.

These days, Members often leave their families at home to avoid being tagged a “Washington insider.”

“It’s not as if we’re strangers in the Senate,” said Alexander, who used to organize Tuesday bipartisan breakfasts for Senators. “We see each other all the time, but we don’t have many opportunities to get to know one another in-depth. … What’s lacking are the opportunities for deep friendships across party lines, and there’s not as much of that today as there was 20, 30 or 40 years ago.”

Kirk said the little things add up.

“The reality is bipartisan cooperation and seeing eye-to-eye can be directly related to the amount of time you spend with each other,” said Kirk, who added that he and Manchin often discuss legislation on the budget and debt ceiling.

They’re not the only ones who’ve noticed that bonding time across the aisle often results in faster-moving legislation.

“The goal of the Senate is not to be bipartisan, but the Senate works a lot better when Senators know one another and understand what their common interests are,” Alexander said. “We can’t get much of anything important done unless Republicans and Democrats agree, and you’ve got to know each other before you agree.”

Alexander often hangs out at the bipartisan prayer breakfast and dines with Democrats such as Sen. Mark Pryor (Ark.).

“We like to talk football, we’re from adjoining states, and we got elected in the same year. We enjoy having dinner together,” Alexander said.

Although his bipartisan breakfasts — once attended by 40 Members — grew “harder and harder to schedule,” Alexander hasn’t given up his hope of bringing Democrats and Republicans together. He now works with Sen. Charles Schumer (D-N.Y.) to host wine-and-cheese receptions in the Rules Committee Room following Monday night votes. On average, 10 to 12 attend.

But the time issue always circles back. Alexander’s numerous experiences scheduling bipartisan events have taught him that bringing Democrats and Republicans together is no easy feat.

“Most of our days start at 6 a.m., and they’re not over until after dinner or at night,” he said. The Senate “is a busy group of 100 men and women, and it’s difficult to insert anything else into those schedules.”

“It’s hard for them to find free time,” said Morella, who is now an American University faculty member. “Situations don’t bring them together; it’s not their fault.”

Manchin said Members should make bipartisan activities a higher priority. He and Kirk plan to continue their bipartisan dates and hope their colleagues will eventually follow suit.

But in today’s Congressional culture, that’s improbable. After a recent luncheon, Manchin invited Kirk to a Democratic budget meeting. Kirk hesitated because the meetings are typically partisan affairs, but Manchin wanted to shake things up.

That turned out to be harder than they thought. When Kirk entered the room full of Democrats in the middle of Sen. Kent Conrad’s (D-N.D.) budget briefing, he was asked to leave. The meeting was “Democrats only.”