As the dust settles following a whirlwind of events leaving the top leadership positions at both the Department of Homeland Security and Immigration and Customs Enforcement suddenly open, many are questioning President Donald Trump’s rationale. Everything started last Friday when seemingly out of the blue Trump pulled his nomination of Ronald Vitiello for director of ICE. Trump’s explanation for his decision left many befuddled given Vitiello’s 30-year history with ICE and tough talk about walls. “Ron’s a good man,” Trump stated, “but we’re going in a tougher direction.”

It appears that Trump’s decision didn’t sit well with DHS Secretary Kirstjen Nielsen, who on Sunday tendered her resignation. In her resignation letter, Nielsen wrote, “Despite our progress in reforming homeland security for a new age, I have determined that it is the right time for me to step aside.” She also implied that much of the blame for the current border crisis lay with Congress, writing, “I hope that the next Secretary will have the support of Congress and the courts in fixing the laws which have impeded our ability to fully secure America’s borders and which have contributed to discord in our nation’s discourse.” Kevin McAleenan, head of Customs and Border Protection, will act as Homeland Security secretary.

A couple things can be gleaned from recent events. First, Trump is clearly frustrated by the DHS’s lack of success in stemming the migration crisis at the border — a crisis that, as Nielsen noted, Congress has thus far refused to act on. Worse, it’s a crisis Democrats have exacerbated for their own political aims, while they flippantly throw concern for national security and protecting the rights of American citizens under the bus. Meanwhile, by pulling Vitiello’s nomination, Trump claims a “get tougher” message, but his decision may also have been in deference to the opinion of senior adviser Stephen Miller and ICE union boss Chris Crane. In other words, it looks like there was a lot of internal politics behind this decision.

This also appears to be the motivation behind Nielsen’s decision. Nielsen, who supported Vitiello, recognized that change was coming, and maybe in a direction she was not as comfortable with.

Second, the big picture. Trump is shaking things up in his effort to deal with the border crisis and make it the central political issue for the nation. Obviously, he believes that a leadership course change is necessary to meet his stated desire to get tougher on border security. Trump may also be seeking less pushback from within the DHS over his threats to shut down the southern border should Mexico not get more aggressive in efforts to stop the caravans of migrants flowing through its country.

Arguably, one of the biggest issues that won Trump the presidency was his promise to aggressively tackle the problem of illegal immigration. Now as the border crisis seemingly only gets worse, Trump recognizes that if he doesn’t produce significant results, it could prove costly for his 2020 reelection bid. He knows Americans don’t want more of the same.