If I had polling in Texas that showed Bush would swing the vote there 2 or 3% it would absolutely be worth having him speak. The real question is how much voters are persuaded by public endorsements anymore.
A) is the person only going to be exclusively discussing the issues you agree with, and won't be bringing up, say, anti-LGBT stuff or union-busting
B) do you sincerely expect this will help you get some certain helpful goal eg winning Ohio, forcing the GOP to waste money in Ohio, etc; or at least doesn't hurt your goals.
I think it is reasonable to suspect that Kasich at the convention does meet both criteria, while, say, Bernie getting Joe Rogan's endorsement generally met A but wasn't particularly helpful on B. I believe Republicans generally though Zell Miller at the 2004 GOP convention met both, and also with Joe Lieberman speaking at the 2008 GOP convention.
The line would be Biden making policy concessions to never-Trump Republicans in exchange for endorsements. As long as that doesn't happen and there's the chance it draws reluctant Republican voters away from Trump, I don't care who they bring out to continue sapping percentage points from Trump or at least force him to spend money to avoid sinking further.
Well, Bush would probably not be the best person to speak at the convention, given his own brother did not want to carry his baggage on his failed presidential campaign.
Biden is running on a unity platform and "restoring the soul of the nation." He will be the President of Republicans as well, and though they may disagree, it behooves his message to demonstrate an ability to bring people together across political aisles for the betterment of the country.
This is what always frustrated me. 50% of the electorate isn't going to just disappear because we want them to.
I appreciate these responses but here's my concern. Not to take anything for granted, but it's looking likely that Biden will win the election pretty convincingly. And while he has pretty solid support overall from the progressive wing of the party, he's also clearly going for the suburbanite voters that are more center and right leaning. And in this election he doesn't really have to do anything other than not shit himself to win their vote. He can still have a more left leaning platform and attract these voters because he's not Trump
But looking ahead, it's pretty unlikely the Trump wing of the GOP will disappear, and they may keep trying to push the party to outright ethno-nationalism. I think a lot of people here have thought that this will lead to sustained losses until we get back to a "traditional" GOP that's economically conservative but more socially liberal. And then the two parties would become those voters and some more conservative current Democratic voters (Manchin, etc) and some of the more center leaning democrats combining with the emerging progressive wing to be the new Democratic Party.
My worry is instead this could lead to the Democratic party looking to take over the middle of the political spectrum, grabbing all those former Republicans and combining it with the more technocratic/center wing of the Democratic Party. The Democratic Party would look back on this election and see all the support they got from the suburbanites and modify their platform to appeal to them, since simply being "Not Trump" won't be enough for their vote anymore. The left would really have nowhere to go, and the Democratic Party wouldn't really be incentivized to support progressive policy because they already have current established democrats plus all of the voters turned off from the current nationalistic, white supremacist GOP.
Essentially, my point is right now, Biden can accept endorsements and whatever from these Republicans to go after suburban/swing voters without making any policy concessions
now. But in the future, when the GOP is still this ethno-nationalist party but with a more competent candidate who can appeal to those swing voters with dogwhistles, what's to stop Biden/Democrats from modifying their platform rightward to keep these voters? What's the incentive to continue pushing more progressive policies and risk losing these votes for an unreliable progressive vote? Sorry if this is a bit all over the place but hopefully my point comes across. His platform does have a lot of progress, but my worry is that future elections will slide back rightward instead of continuing left. He can get away with a more progressive platform because of who he's running against, but what will be the platform when he's running a tighter race and has to make a decision to appeal explicitly to the progressive wing or center/swing voters?
