Retirement speeches were droning on in the Minnesota Senate on Thursday afternoon after the last gavel had fallen on the year's lawmaking. But no one in the press rooms dozed off.

Rumor had it that a senator whose retirement had not been previously announced would rise to say goodbye -- one David H. Senjem of Rochester.

Per usual all year, the rumor mill had it wrong. When the 69-year-old Senate majority leader finally rose, it was to say "see you next year."

That may not have been the message the hard-right half of his caucus was hoping to hear from their more moderate chief.

In the final days of the 2012 session, the division between weak-Tea and strong-Tea conservatives in the Legislature's Republican majority caucuses was laid bare on the electronic vote boards and in Twitter tweets for the Capitol-curious to see.

It's a bigger split than many watchers knew. Meaner, too.

The vote on a $496 million bonding bill -- midsized, as these things go -- revealed the size of the two factions. Republicans voted 39-32 in the House, 18-19 in the Senate.

That Senate vote is astonishing when one considers who carried the bill -- bonding chair David Senjem. Never before in Capitol press corps memory was a Senate majority leader's personally crafted, high-profile bill so openly rejected by so many in his own caucus.

The meaner side of the GOP split popped into view on Twitter, the Capitol's busy e-venue for all manner of political thought. Tweets by Republican Sens. Gretchen Hoffman and Sean Nienow went so far as to hint that a coup to topple Senjem might be in the works.

Nienow, a two-termer from Cambridge, vented his frustration photographically. "Hey look! Here's what was served up for the fiscally conservative agenda this year in the #mnsenate!!!" he captioned a photo of an empty plate.

I asked him what he and other members of the group he calls simply "the conservatives" wanted on that plate. He ticked off his personal menu:

• "A bonding bill that was more conservative," he said. (But the House had already demonstrated with a bonding bill for Capitol repairs that a smaller bill couldn't get over the requisite 60-percent supermajority hurdle.)

• A stadium bill with a source of financing other than "a minicasino in every bar," and with a referendum in the city of Minneapolis. (Goodbye, Vikings.)

• A constitutional amendment sent to the voters to require a supermajority vote of the Legislature to raise taxes. (Watch out for higher local property taxes if that lawmaking hurdle is erected.)

I noted that at least two of those wishes would have been opposed by the people who paid for the Republican resurgence of 2010 -- the Minnesota business community. Nienow's response was revealing:

"I've said for years, big business loves big government. I'm no fan of big government, and by extension, I'm not necessarily a fan of big business. Businesses create jobs, so to that extent, we don't want to undercut them. ... But big business is not about free markets and free choice. It's about business."

If business donors thought their 2010 campaign largesse assured them a pliant majority, ready to deliver things like Southwest Corridor light-rail transit, outstate convention centers and a requirement that online retailers collect sales tax, they're rethinking today.

For decades, Republican success in Minnesota and nationally has rested on a coalition that knit together social conservatives with businesses seeking lower taxes and less regulation.

That coalition has proven remarkably durable. But at the 2012 Legislature, it looked increasingly unstable. Many of the newly elected social conservatives are also libertarians. They're quite willing to shrink even the government activities that businesses need and want.

Many businesses, meanwhile, found their wishes ignored or, in the case of the stadium and bonding bills, enacted with more DFL than Republican votes. Some businesses also dislike the 2011 decision to put a constitutional amendment banning same-sex marriage on the ballot.

The intra-GOP divide as observed from the Capitol basement was often cast as moderate vs. conservative. I'd say labels "probusiness conservative" vs. "populist conservative" better describe the split. My guess is that more than a few business campaign donors saw it that way, too.

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Lori Sturdevant is a Star Tribune editorial writer and columnist.