Hypothetically speaking, when the new Senate convenes, if there were a razor-thin Republican majority, could the Democrats hold their noses & unite to vote for a spoiler like Romney, Collins, or Murkowski as majority leader to unseat Mitch McConnell?
The quiet understanding of the coalition would be that leadership roles would still all go to Republicans, but their promise to the Democrats would be to at least allow things like cabinet nominations go to an actual vote, instead of allowing Mitch to just refuse to bring them before the Senate at all... and promising to reward any Republicans who went along with it by promising them powerful roles in a future Democratic-majority Senate?
On one hand, the Republican Party would threaten to unleash hellfire & vengeance upon them. On the other hand, Romney is ALREADY on the RP's shit list... and going along with the Democrats would give Romney (and Utah) way more influence & power than he'd ever have in a McConnell-controlled Senate.
This assumes, of course, that Chuck Schumer could be persuaded to convince the Democrats to officially vote for Romney as their leader instead of symbolically voting for him, in the hope that if it came down to McConnell vs Romney, Murkowski and/or Collins would hold their nose(s) and vote for Romney instead (overcoming a Pence-broken tie in favor of McConnell).
As safety measures, they could amend the rules as follows:
* It takes a motion by 60 Senators to vote to end a filibuster. There can be at most one such motion per day for any one issue. Each time such a motion fails, the number of Senators required decreases by one, imposing a practical limit of 10-20 days anyway (after 20 days, even a 40-60 minority could end a filibuster)
* Romney might technically be the Senate Democrats' leader, but he'd delegate all Partisan duties to Schumer
* At any time, a majority of Democrats could elect a new leader, knowing it would almost certainly trigger a new Majority Leader vote among Senators that would flip it to Republicans, since Murkowski and/or Collins would probably support the Republican leader instead.
Building on the palace intrigue, the Democrats could STILL partially smack down McConnell by inducing the REPUBLICANS to vote for someone like Murkowski or Collins instead of Mitch. Even if it came down to Romney vs Murkowski or Collins & the official Republican choice won, it would still achieve the goal of kicking Mitch to the sideline.
Anyway, if Schumer were willing & able to pull it off for the sake of dealing a big "fuck you" to McConnell, could they pull it off? And could they actually GET 100% of Senate Democrats to support Romney for the sake of a tiny potential for occasional victory, vs total practical irrelevance for the next 2 years?
I'm not sure, but I think this is something like what happened a few years ago in Britain's Parliament. I think the Conservatives failed to get an absolute majority, and convinced the LibDems to make a brief deal with the devil to share power as a combined majority w/the Tories instead of allowing Labour to win control by a plurality.
I do know that in countries like the US & Britain, coalitions like this usually end up being extremely fragile. On the other hand, the Senate by its very nature tends to be a lot more uniformly center/center-right than the House, so there's less risk of an AOC-like spoiler taking his/her ball & going home to spoil the game for everyone.