Sen. Ron Johnson
Ronald (Ron) Harold JohnsonTop cops deflect blame over Capitol attack NRSC chair Scott calls for party unity: 'The Republican Civil War is now cancelled' GOP senator raises uncorroborated claims about 'provocateurs,' 'fake Trump supporters' at Capitol riot hearing MORE (R-Wis.) said on Monday that he is concerned about a "leadership void" at the Department of Homeland Security (DHS) amid talks of a shake-up of top staffers.

"In addition to congressional dysfunction, I am concerned with a growing leadership void within the department tasked with addressing some of the most significant problems facing the nation," Johnson, the chairman of the Senate Homeland Security and Governmental Affairs Committee, said in a statement on Monday.
Johnson's statement comes after Trump announced that Homeland Security Secretary Kirstjen Nielsen
Kirstjen Michele NielsenLeft-leaning group to track which companies hire former top Trump aides Rosenstein: Zero tolerance immigration policy 'never should have been proposed or implemented' House Republican condemns anti-Trump celebrities during impeachment hearing MORE would be leaving her post and that Kevin McAleenan, the commissioner of Customs and Border Protection, will lead DHS on an acting basis until a permanent replacement for Nielsen is chosen.

In addition to Nielsen, CNN reported that White House adviser Stephen Miller is pushing for Lee Cissna, the director of United States Citizenship and Immigration Services (USCIS), and John Mitnick, the department's general counsel, to be dismissed.
A Trump administration official told CNN that there are also questions about the future of Claire Grady, under secretary of management at DHS.
Sen. Chuck Grassley
Chuck GrassleyYellen deputy Adeyemo on track for quick confirmation Durbin: Garland likely to get confirmation vote next week Garland says he has not discussed Hunter Biden case with president MORE (R-Iowa), the chairman of the Senate Judiciary Committee, went to bat for Cissna on Monday amid talks that Miller could be trying to force him out.

Grassley noted that Cissna previously worked for him on the Judiciary Committee and is "doing an excellent job leading USCIS."
Commissioner McAleenan will do gr8 job @ DHS. Has gr8 support from 1 of smartest immigration policy minds I know: US Citizenship & Immigration Services Dir Cissna who worked w me for 2yrs on judic cmte & is doing an excellent job leading USCIS
— ChuckGrassley (@ChuckGrassley) April 8, 2019
But the moves signal that Trump is seeking to shake up his team amid frustration over the spike in migrant families crossing the southern border.
He yanked his nominee to lead Immigration and Customs Enforcement late last week because he said he wants “to go in a tougher direction.”