US President Donald Trump has formally nominated Kirstjen Nielsen to lead the Department of Homeland Security (DHS). Nielsen, 45, currently serves as deputy to Chief of Staff John Kelly, whom she worked under when he headed the DHS prior to taking the position at the White House. “There will be no on-the-job training, she’s ready from day one,” Trump said. “Kirstjen was integral to the progress we have made in controlling our borders, confronting gang violence, preparing for disasters and protecting aviation security,” the president added, calling for Congress to “put politics aside” and confirm her nomination. If confirmed by the Senate, Nielsen will lead an agency charged with securing the nation’s borders and airports, enforcing immigration laws, coordinating disaster relief efforts and overseeing the Secret Service and Coast Guard. Nielsen also served on former President George W. Bush’s Homeland Security Council.