Trump’s emergency decree could end shutdown, but at what cost?

“We’re going to be in 2020 before this gets resolved,” said Walter E. Dellinger III, a former solicitor general in the Clinton administration, adding: “If they are just planning where to build slats, judges are unlikely to decide that requires expedition in the Supreme Court. I think they would recognize the wisdom of going slow.”

If, in the end, the Supreme Court were to rule that emergency-power laws give Mr. Trump authority to proceed, he would probably face still more litigation with property owners over whether the government may use eminent domain to force them to sell their border lands. There may be little time left in his term after all that to add more than a few miles, if any, of barriers to the 1,954-mile border, which already has 654 miles of fencing.

And if the court instead eventually ruled against him, Mr. Trump could honestly tell his supporters that he tried, and then vow to renew the push if he is re-elected. Indeed, he has suggested that he would relish still having the issue of wall to once again rev up supporters in the campaign. He wrote on Twitter late last month that Democrats may have enough votes to stop his wall, “but we have the issue, Border Security. 2020!”