When it comes to the $1.3 trillion spending package Donald Trump signed into law last week, the president has struggled to decide what he thinks is in it. On Friday morning, for example, Trump complained that the omnibus didn’t fund his border wall. On Friday afternoon, he switched gears, saying the bill included a “down payment” on the wall, and construction would begin “immediately.”

Behind the scenes, meanwhile, the president apparently realizes, at least on some level, that Congress hasn’t authorized any funding for his wall proposal, which is why he’s looking elsewhere for the money. The Washington Post reports:

President Trump, who repeatedly insisted during the 2016 campaign that Mexico would pay for a wall along the southern border, is privately pushing the U.S. military to fund construction of his signature project. Trump has told advisers that he was spurned in a large spending bill last week when lawmakers appropriated only $1.6 billion for the border wall. He has suggested to Defense Secretary Jim Mattis and congressional leaders that the Pentagon could fund the sprawling project, citing a “national security” risk.

Pressed for confirmation yesterday, White House Press Secretary Sarah Huckabee Sanders didn’t deny the president’s plan, saying only that the administration is “going to continue moving forward” with wall plans, though she “can’t get into the specifics.”

Before anyone gives the president credit for outside-the-box thinking, it’s worth emphasizing that it’s unlikely he came up with this idea on his own. On Saturday night, right-wing media personality Ann Coulter appeared on Fox News, and made this identical suggestion to Jeanine Pirro, a close White House ally.

The next morning, Trump declared that the Defense Department is now “rich,” and can therefore afford to use money from its budget to pay for the president’s wall.

The fact that Trump turns to conservative media hosts to staff his administration is well documented, but the president’s dependence on what he sees on television extends beyond personnel: the White House’s policy agenda, such as it is, is often shaped by whatever Trump happens to find compelling while watching TV.

Complicating matters, of course, is that the president doesn’t have the legal authority to take federal funding devoted to one purpose and then redirect it to some other purpose. As the Post’s article added:

[T]he military is not likely to fund the wall, according to White House and Defense Department officials. The Pentagon has plenty of money, but reprogramming it for a wall would require votes in Congress that the president does not seem to have. Taking money from the 2018 budget for the wall would require an act of Congress, a senior Pentagon official said. To find the money in the 2019 defense budget, Trump would have to submit a budget amendment that would require 60 votes in the Senate, the official said.

It’s entirely possible that the president doesn’t much care about the legal constraints, but so long as other officials reject his indifference, Trump’s Coulter-inspired idea probably isn’t going anywhere.

Postscript: A reporter asked Sarah Huckabee Sanders yesterday for information on how the president is working toward Mexico paying for the border wall, as Trump promised during his campaign. “When we have an announcement on that I’ll let you know,” she replied.