Conservatives who hate Romney tend to also like Tulsi, but I can't see them backing Sinema. Progressives obviously stay home. Turnout will drop 20-30% barring a third and fourth party, but the old man will win a majority of the participating Never Trumpers and Rockefeller Democrats.
The few voters remaining after removing everyone who has actual beliefs will respond to Romney's "presidential demeanor" and deplore Sinema's unprofessionalism, and her strategy of refusing to engage with party grassroots will leave her with a major fundraising disadvantage.
I'd disagree with this. These conservatives you speak of who view Gabbard favorably also tend to view Sinema favorably. They view both Sinema and Gabbard as "reasonable" Democrats who they can work with. Given this, and given that much of the Republican base absolutely despises Romney and Cheney, I'm inclined to believe that the Sinema/Gabbard ticket would win. Sinema would hold the moderate suburbanites who backed Biden last year, and would potentially expand Democratic gains among them, while Gabbard could bring back many of the Obama/Trump voters.
