He signed it five days ago. How can he have changed his mind already?

And if he feels this strongly, why did he sign in the first place? Not that signing something and then immediately regretting it when his base freaks out would be new to Trump.

Assuming this report is true, though, we’ve found a rare patch of common ground between POTUS and his predecessor. Both of them wanted to set immigration policy via royal decree because Congress wouldn’t bend to their wishes.

He has instead gone on the offensive, complaining to aides about why he could not just create an overarching executive order to solve the problem, according to two people familiar with the deliberations. Aides have had to explain to the president why a comprehensive immigration overhaul is beyond the reach of his executive powers.

And privately, the president has groused that he should not have signed the order undoing separations

Mr. Trump’s careening from one extreme to another has been a staple of his campaign and presidency, allowing people to hear what they want in what he says — and leaving his White House to sort through a messy pile of conflicting directives and Congress to grasp for clues about which bills he might support.

Careening from one extreme to another not only is a staple of his presidency, it’s been a staple of immigration policy just within the past week. Remember, House conservatives seemed prepared to vote for a compromise bill that would grant DREAMers amnesty in return for the wall and various restrictions on legal immigration — but they wavered because they weren’t sure if Trump would back them up or not. Privately the White House is telling those reps that POTUS will sign the compromise bill if it lands on his desk; publicly, however, Trump keeps saying that it’s a waste of time for the House to vote on immigration when there aren’t 60 votes for the bill in the Senate. So conservatives are balking and the House is huddled up trying to forge a new compromise, one possibly expanding E-Verify and forging a new rule that would allow families to be detained together indefinitely while their asylum applications are pending. But there won’t be 60 votes for that bill either. Will Trump support it anyway or do another round of his “privately supportive, publicly skeptical” shtick?

House Republicans have grown stoic about his odd changes of heart, practically expecting to be stabbed in the back as he flits from the restrictionism favored by his base and his own instincts to the softer hand overwhelmingly favored by the media and the elites whose approval he quietly craves:

“You fear the tweets in the morning. How many policies will he undo today?” said Representative Ileana Ros-Lehtinen, a Florida Republican who’s not running for re-election. “It’s such schizoid policymaking by tweets, where what you say on Monday may not last until Friday.”

Some Republicans said they’re afraid of “getting omni-ed” — a reference to Trump’s last-minute threat in March to veto this year’s spending bill, known as an omnibus, that took months to negotiate. He ultimately signed it only after conservatives scrambled to explain why they backed such an expensive bill and why it didn’t fully fund Trump’s wall on the U.S. border with Mexico.

[Rep. Walter] Jones said he “never will forget” the time in mid-2017 when news reports said Trump told senators in a private meeting that the House Republican’s health-care bill was “mean” — just weeks after the president and House members held a jubilant Rose Garden celebration of its passage. The bill went nowhere in the Senate.

I’d forgotten about that — but yeah, from Rose Garden to “mean” in the span of a few months is an extreme vacillation even for Trump. And the stakes are high for congressional Republicans in getting crosswise with him given the unshakeable loyalty he commands from the party’s base. It’d be embarrassing but ultimately no big deal for House conservatives to support an amnesty bill only to have POTUS give it thumbs down *if* the loyalties of Republican voters were more divided. But voting for the compromise bill not knowing if Trump will denounce it as a sellout on the right’s core cultural issue all but invites a primary challenge if you represent a deep red district. It speaks volumes about how unpopular child separation was nationally that House and Senate Republicans were willing to get ahead of Trump in denouncing it, with Ted Cruz going so far as to propose legislation ending the policy before Trump canceled it himself. Which may help explain why Trump regrets the cancellation — for once, Republicans in Congress stared him down and he blinked. They’ve abandoned him before during a political storm, only to come crawling back once they realized he wasn’t backing down. If Trump had dug in hard on separating children, congressional Republicans would have been rent in half by the opposing political pressures, probably forced in the end to side with Trump lest the GOP base freak out. He did them a kindness by relenting.

As for changing U.S. immigration policy via executive policy, that’s a no-go for some of the same reasons Obama’s executive amnesties were illicit but also for some different ones. Jonathan Adler has a brief but useful history of SCOTUS jurisprudence on due process at the Volokh Conspiracy. It’s true that non-citizens aren’t owed all the same constitutional protections as citizens, but due process in some form is one they have in common. You can intuit why: If we’re going to do something as extreme as punting someone out of the country, we need to do at least a little adjudicating to make sure they have no right to be here. People with valid asylum claims are entitled to enter under U.S. law; if you take POTUS’s tweets on this subject seriously, he’d end the asylum process altogether in the name of sealing the border. That position is more popular among the population than the media might think, I’m sure, but the fact remains that Congress won’t be taking a shot at ending either asylum or due process. Hence Trump’s pipe dream of using his executive authority to order summary expulsion for anyone caught at the border.