When ballots are tallied Tuesday night, a handful of House and Senate seats will determine whether the imbalance of partisan power in Colorado reaches a level not seen since World War II.

Democrats, who already hold trifecta control of both legislative chambers and the governor’s office, stand one seat shy of a two-thirds supermajority in the Senate to mirror their current supermajority in the House — if Democrats in that chamber can keep the gains they made in 2022.

But Republicans also see an opportunity to claw their way out of the political wilderness. They need to flip only three seats that went blue by razor-thin margins to break the supermajority in the House.

An unfavorable Senate map and wide margins in the House mean that a full flip in party control in either chamber is all but impossible this time.

But the millions of dollars being spent on the races — often by outside groups and party-aligned political committees — show an emphasis on strengthening, or breaking, the parties’ respective footholds in the Capitol.

More than $7 million in outside spending has poured into the Senate races, and about $4.5 million has flowed into House races, according to the most recent filings.On the Senate side, the vast majority of that money has gone to three races: District 12, in El Paso County, and District 5 and District 6, both in the southwest part of the state. All those seats are currently occupied by Republicans.

“I might have been naive, but I didn’t expect (my race) to get that much attention from everybody,” said state Rep. Marc Catlin, a Montrose Republican who’s looking to move to the Senate in a race that’s drawn more than $3 million. “But it goes to show how much a two-thirds majority is worth.”

Advantage on rules, vetoes, amendments

A supermajority generally allows the governing party to do three things without relying on the minority party: Override vetoes, refer state constitutional amendments to voters and change floor rules on the fly. Less officially, it also typically results in strong majorities on committees — the first stop for all legislation in each chamber, where bills can live or die by a single vote.

Speaker Julie McCluskie, a Democrat who’s set to run for a second term as the House’s leader later this week, shrugged off the importance of her caucus maintaining its two-thirds grip on the chamber.

The size of their majority — 46 strong in the 65-seat chamber — means there’s typically been room for intraparty disagreements, without the need to shore up defections with Republican votes.

Outgoing Senate President Steve Fenberg, a Boulder Democrat, likewise downplayed the importance of attaining a supermajority in that chamber.

It would probably be easier to put a constitutional amendment on the ballot through traditional signature gathering, he said, than to keep a 24-member supermajority caucus lockstep through stiff partisan opposition in the 35-seat Senate. (Senate Democrats currently have 23 seats.) Overriding a veto, particularly from a Democratic governor, Jared Polis, would likewise be naturally divisive.

“For me, it’s never been that important to get a supermajority, and it hasn’t been the goal. I think this is something that’s largely interesting for the press to write about,” Fenberg said in an interview.

Warning against Democratic overreach could also serve as a fundraising pitch for a Republican Party at the nadir of its influence in state politics, he added.

“They’re not going to get the majority, so the pitch, ‘Help keep us from the complete wilderness,’ probably isn’t the most appealing pitch to a donor,” Fenberg said.

Senate Minority Leader Paul Lundeen, a Monument Republican, says his 12-member caucus has been able to exert more influence than it could from a superminority position. He points to the successful blockade of a proposed constitutional amendment in April.

That measure, if ultimately approved by voters, would have changed the state constitution to allow the legislature to remove the statute of limitations for victims of childhood sexual abuse. He and other Republicans worried that change would have broader effects on civil law and legal certainties.

“(An effective Republican minority) is the last handle of common sense that is available in the legislative process, the political process — and Colorado Republicans are hanging onto that handle,” Lundeen said.

He and Fenberg offered similar predictions: They don’t think Republicans will fall to superminority status in the election.

Fenberg, for his part, said the Democratic majority as it stands now is artificially inflated: Sen. Kevin Priola, who is termed out from running again in his solidly red district, switched parties two years ago. That means Democrats effectively would need to flip two seats to cross the supermajority threshold.