The GOP siding with Cruz against Trump was a poison pill. At that point, Trump's claim to fame was that he was an outsider. Cruz, by benefit of having stuck to his guns in DC and fought the GOPe in the Senate was also considered an "outsider"--he lost that when the GOP climbed on board as the other candidates dropped out.
One of the big arguments I saw was that with the GOP hacks on board, it just proved that Cruz was GOP-e all along, and only Trump was a true outsider.
That 'support' hurt him, imho, as intended.
So if the GOPe publicly supported Trump, that obviously proves the argument that they supported Trump. And if they publicly supported Cruz....well, that
also proves they supported Trump?
That's a "head I win, tails you lose" rhetorical rabbit punch, Smokin' Joe, unworthy of your pugilistic namesake. It's also not even the argument made earlier in this thread, when people were talking about actual endorsements and not poison pill endorsements. Someone dared me to produce evidence of an actual endorsement for Trump, I did, so then it gets switched around to mean the exact opposite? I'm not buying that.
On top of that, I don't think the poison pill argument holds anyway. Sure, it would have been a "poison pill" endorsement, but only for those fervent anti-establishment types who were already in Trump's corner anyway. (But who repeatedly celebrated any such endorsements their own candidate got nonetheless). The people those endorsements were directed at were anti-Trumpers, including not just supporters of Kasich, but supporters of Rubio and others who might otherwise just stay home. And to
those people, such endorsements weren't "poison pills." Further, I'd suggest that the people who actually made those endorsements -- Bush, Romney, Rubio, etc.., didn't see
themselves as "poison pills", and certainly weren't trying to sabotage Cruz with their endorsements.
Note the GOP didn't call for Kasich to drop out, so the non-Trump vote was split between Kasich and Cruz.
I disagree -- there were calls pretty early on for Kasich to drop out, but he was consistently having none of that. They just gave up after awhile. But additionally, some expressly did call for Kasich to drop out:
Romney said that a vote for Kasich amounted to a vote for Trump, and encouraged all anti-Trumpers to unite behind Cruz:
http://www.cincinnati.com/story/news/politics/elections/2016/03/18/mitt-romney-m-voting-ted-cruz-not-john-kasich/81980750/Otherwise, when the race is down to just Trump, Cruz, and Kasich, I think an endorsement of Cruz, and urging anti-Trump voters to unite behind him is the functional equivalent of asking Kasich to drop out anyway -- a distinction without a different.