With one eye as always on the construction of his wall, Donald Trump has fired his secretary of homeland security, the notoriously restrictive Kirstjen Nielsen.

Donald Trump has continued to up the ante over immigration. On Sunday, April 7, he added his secretary of homeland security to the already long list of close associates dismissed by tweet. Nielsen was linked to the most controversially oppressive policies for reducing immigration from Mexico. She failed to get results, however, and the White House announced her replacement: Kevin McAleenan, who was until recently commissioner of U.S. customs and border protection.

“Our country is full,” Trump later stressed while justifying his plan for a border fence to make illegal immigration impossible. The president, who didn’t hesitate to let go of one of his most loyal followers, is keen to calm the worry growing around him and his circle in the face of glaring signs that growth is slowing. Essentially, the soft blow expected to the U.S. economy could seriously jeopardize the success of the property billionaire’s campaign to re-enter the White House in 2020. The chance of this snag has led him to play up his populist strategy of xenophobic tirades. Hence his impatience for real results for his 2016 campaign promise of constructing an anti-immigration wall along the southern border.

100,000 Mexican Migrants Interrogated

Trump’s decision to shake up the leadership of his anti-immigration bureau comes about despite statistics from border police revealing the inefficiency of the administration’s previous measures such as the directive to extend the wall that already exists along some stretches of the border, or the deployment of tens of thousands of military personnel to support border protection services. In March, some 100,000 interrogations of migrants from Mexico and Central American countries, including Honduras, El Salvador and Guatemala, were recorded, the highest monthly level for 10 years.

On Sunday, April 7, after overruling Congress and declaring a state of emergency to finance his wall, Trump issued a warning to Mexican authorities: “Mexico must apprehend all illegals and not let them make the long march up to the United States, or we will have no other choice than to Close the Border and/or institute Tariffs.” For example, he could threaten new customs duties on Mexican products.