Michigan once served as a national bastion for organized labor, economic prosperity and moderate Republicans. Not anymore.

This week in Lansing, a Republican governor who ran as a business-minded moderate rammed a right-to-work bill through in a lame-duck session. Democrats and unions revolted, threatening the second coming of the Wisconsin recall.

But the law’s passage is symbolic of the kind of changes that continue to hit the economically distressed state: demographic, political and personal. And nowhere are these changes more imminent than the congressional delegation, where the average age of a Michigan Democrat is 73.

“I do think people feel this way in my home district,” said Rep.-elect Dan Kildee, a Democrat who will succeed his 83-year-old uncle, 18-term Rep. Dale E. Kildee, in January. “Dale has served this district for a long, long while. It’s a generational shift.”

On Monday, almost all the Democrats in the Michigan delegation huddled with Gov. Rick Snyder at the state capitol. Sen. Carl Levin, a six-term Democrat, led what would become a fruitless and frustrating conversation.

One by one, members said their piece, imploring Snyder not to sign the bill. They pleaded with him to pursue the law next year instead. They asked him to line-item veto the appropriations attached to the final bill — a maneuver that makes the consequential law referendum-proof.

The senator’s older brother, Rep. Sander M. Levin, delivered a particularly passionate argument by recalling negotiations on a 1965 landmark law for state organized labor, the Public Employment Relations Act, while he was a state lawmaker. His adversary? Republican Gov. George Romney.

None of it worked. The most senior members of Congress were powerlessly in awe of the state of their state. Democrats left the meeting more frustrated than when they arrived.

“We made our case as strongly as we could, hoping he would veto it,” said Rep. Gary Peters, D-Mich., who said the governor didn’t engage much in the discussion. “It seemed he didn’t really understand what right-to-work was about, or these issues. It really was stunning.”

Michigan Democrats have reason to be frustrated — but not because of Snyder. Despite their seniority on Capitol Hill, the Democrats’ clout has declined in the past decade.

Much of this is because of gerrymandering of the state’s congressional and legislative districts. Democrats dominated statewide politics for most of the past decade but held legislative minorities after two devastating cycles: 2000 and 2010. Republicans redrew the map in their favor in 2001 and perfected their gains last year.

When Congress returns in January, Republicans will control nine of the state’s 14 House seats. Democrats made minimal gains in the state legislature last month, but Republicans will continue to control both chambers next year.

Meanwhile, President Barack Obama won the state by about 10 points, and Democratic Sen. Debbie Stabenow won by more than 20 points.

But those two victories somewhat masked the fact that Democrats are on the brink of change in the delegation — and it may begin in 2014. Carl Levin, chairman of the Senate Armed Services panel, hasn’t said whether he’ll run for a seventh term. If he retires, it would open the door to a highly competitive open-seat race featuring one or more House members.

The next decade will also likely bring the changing of the guard in the districts of Democratic Reps. John D. Dingell and John Conyers Jr., the No. 1 and 2 most senior House members, who have served for a combined 52 terms.

Conyers, entering his 25th term, remains ranking member of the Judiciary Committee. But Dean of the House Dingell, entering his 29th term, lost his ranking slot on the Energy and Commerce Committee in 2008 in a power battle with then-Speaker Nancy Pelosi, D-Calif. It’s unlikely either Michigan Democrat will hold a chairman’s gavel again. (That’s not necessarily the case for 81-year-old Sander M. Levin, ranking member on the powerful Ways and Means Committee.)

Still, you’d be hard-pressed to name a state delegation with more committee leaders per capita on Capitol Hill than Michigan. That’s because much of the delegation’s clout now lies with its Republicans, who have experienced a transformation of their own over the past decade as the party has shifted right.

The Michigan GOP tradition is rooted in moderate, labor-friendly Republicans — for example, Romney, the late governor and father of the 2012 presidential nominee. Just a few years ago, the delegate boasted center-right members such as Reps. Vern Ehlers, Joe Schwarz, Thaddeus McCotter and Joe Knollenberg. All of them were replaced by more conservative Republicans, except Knollenberg.

“In general, is the Michigan delegation more conservative than in previous years? The answer is yes,” said Schwarz, who has publicly toyed with running as an independent or Democrat since his defeat. “Some of the less senior members of the delegation are much farther to the right than some of the more senior delegation members.”

Schwarz served a single term as a Republican before conservative Rep. Tim Walberg defeated him in the 2006 primary. Rep. Justin Amash, an acolyte of outgoing Texas GOP Rep. Ron Paul, succeeded Ehlers in 2010. Rep.-elect Kerry Bentivolio, a Republican in the same libertarian vein, will take McCotter’s seat in 2013.

To be sure, current GOP Reps. Fred Upton and Dave Camp have moderate streaks, as do colleagues Mike Rogers and Candice S. Miller to a lesser degree. But Upton, a one-time co-chairman of the moderate Tuesday Group, now chairs the Energy and Commerce Committee, and Camp is Ways and Means chairman — roles that require toeing the party line. Next year, Upton’s former swing district will include safer GOP territory, thanks to redistricting.

Then there’s Knollenberg. His former district won’t exist in January. Peters defeated him in 2008, and Republicans eliminated the 9th District in their redraw.

His son, state Rep. Marty Knollenberg, is a political power in the legislature — and the proud author of the controversial right-to-work law.

In a phone interview Wednesday, the younger Knollenberg called it a “game-changing legislation” that “lets the world know we want business to come to Michigan.”

“At the same time, do I think this will help Republicans? I do,” Knollenberg said. “If you look at where the union contributions go, they all go to Democratic candidates.”