Sen. John McCainJohn McCainMcCain made secret trip to Syria A guide to the committees: Senate Webb: The future of conservatism MORE (R-Ariz.) said Tuesday the new Homeland Security secretary has “a lot to learn.”

Jeh Johnson is visiting the border with Mexico for the first time this week since he was sworn into his Cabinet position in December.

McCain tweeted a link to a news article about Johnson’s visit and said “Good—he has a lot to learn.”

During the confirmation process, Republican members of Congress accused Johnson of lacking experience on border-security issues.

Johnson will visit the border in Texas and Arizona on Tuesday and Wednesday, Homeland Security Department spokesman Clark Stevens announced last week.

Rep. Ron BarberRon BarberTen House seats Dems hope Trump will tilt House conducts moment of silence for Tucson shooting anniversary Dem files Ethics complaint on Benghazi panel MORE (D-Ariz.), a member of the House Homeland Security Committee, is hosting Johnson near Tucson. The congressman said he had invited Johnson to tour the border in August. In a letter, Barber told the incoming secretary about the area, where “smuggling of illegal drugs and continues to have one of the highest rates of apprehension for people entering the country illegally.”

Johnson succeeds Janet Napolitano, who now serves as president of the University of California. Johnson worked as general counsel for the Defense Department during President Obama’s first term.