Michael Brendan Dougherty makes the case for Romney to jump into the presidential race:

If Romney should win the primary, it would be an incredible political comeback. It would also be a gift to his party, forcing on the GOP the reality of a new and stable settlement between its factions.

Another Romney campaign might be the one thing that could keep the Trump phenomenon going for many more months. Nothing would convey the party leadership’s utter contempt for their supporters than foisting a failed nominee back on a party that only grudgingly accepted him the first time. There would be no guarantee of a Romney victory in this scenario, and it is more than likely that he would try to swoop in to “save” the party only to be told that his help isn’t wanted. If Romney were foolish enough to listen to the advice of his advisers and joined the race, he would mainly succeed in further weakening the “establishment” candidates that are already in the race while doing nothing to undermine Trump. It is more than likely that Trump would benefit by having Romney in the race, as he would constantly remind voters that they shouldn’t back the “loser” from the last election. If Romney wants to go through the indignity of being humiliated by a huckster, by all means he should jump in the race.

After all, what is the Romney argument against Trump? That he is too wealthy and out of touch with most Americans? That he has no credibility claiming to be a conservative because of a long history of radically different positions? That he is shamelessly lying to the public about what he believes? Anything that can be used to attack Trump can be easily thrown back in Romney’s face, and Romney is the embodiment of almost everything about the party that Trump’s supporters despise. Romney can’t very well attack Trump on immigration when Trump’s pretense of being the most anti-immigration candidate is stolen from Romney’s own playbook, and he can’t out-hawk someone who professes to be the “most militaristic person in the world.” Trump will see your “omni-directional belligerence” and raise you a billion. Romney really ought to be flattered by Trump’s performance, since it is in many respects pays homage to Romney’s own unprincipled and demagogic pursuit of the nomination.