In a rare rebuke to hiw Chief of Staff Gen. John Kelly, President Trump Thursday morning repudiated claims Kelly had reportedly made during a meeting with the Congressional Hispanic Caucus that the president’s views on the wall had "evolved" since taking office.

The details from the closed-door meeting were reported by the Washington Post yesterday, prompting Kelly to take to Fox News to offer a few clarifications. After being quoted as describing the president’s original vision for the wall as “ill-informed”, Kelly explained that, after meeting with experts from the Border Patrol, the administration had decided that building a wall across the entirety of the southern border would be inadvisable.

As Kelly explained, Trump's views on the wall have "evolved", as have his views on DACA, because Trump, like any other politician, has seen his views "evolve" since the days of the campaign.

"...Even the wall. Once we briefed him and told him the real experts...came in and did a survey of the border and there are places where hydrographically or geographically a wall would not be realistic...there are other parts of the southwest border that are so wild or untamed that no traffic that goes through them. "But there's other places we think about 800 miles additional wall, to include the 600 miles of fencing in place, would suffice. This president is very very flexible in terms of what is within the realm of the possible."

Today, Trump appears to have taken issue with Kelly’s phrasing, insisting that "The Wall is the Wall, it has never changed or evolved from the first day I conceived of it." Trump added that the wall had never been meant to be built in an area where natural borders already exist.

"Parts will be, of necessity, see through and it was never intended to be built in areas where there is natural protection such as mountains, wastelands or tough rivers or water,” he added,

The Wall is the Wall, it has never changed or evolved from the first day I conceived of it. Parts will be, of necessity, see through and it was never intended to be built in areas where there is natural protection such as mountains, wastelands or tough rivers or water..... — Donald J. Trump (@realDonaldTrump) January 18, 2018

Kelly confirmed that the administration was exploring ways to get Mexico to pay for the wall, including funding it with the proceeds from visa applications. But Trump took the opportunity to criticize Nafta, insisting that $20 billion for the wall is “peanuts” compared with Mexico’s trade surplus of $70 billion, adding that the wall would be paid for “directly or indirectly” by Mexico.

"The Wall will be paid for, directly or indirectly, or through longer term reimbursement, by Mexico, which has a ridiculous $71 billion dollar trade surplus with the U.S. The $20 billion dollar Wall is “peanuts” compared to what Mexico makes from the U.S. NAFTA is a bad joke!"

....The Wall will be paid for, directly or indirectly, or through longer term reimbursement, by Mexico, which has a ridiculous $71 billion dollar trade surplus with the U.S. The $20 billion dollar Wall is “peanuts” compared to what Mexico makes from the U.S. NAFTA is a bad joke! — Donald J. Trump (@realDonaldTrump) January 18, 2018

Trump said during an interview with Reuters that was published last night that terminating the North American Free Trade Agreement would result in the "best deal" to revamp the 24-year-old trade pact with Canada and Mexico in favor of US interests.

Trump has, of course, used Twitter as a cudgel to push errant members of the administration back in line (a tool he frequently employed when Steve Bannon was still prowling the halls of the West Wing) but Kelly, with his role as gatekeeper to the Oval Office, has typically been above the fray, thanks to his militaristic discipline and unyielding loyalty to Trump.

Could this be the first sign of a major rift between the chief of staff and his boss?