The White House said on Wednesday that Donald Trump would nominate Kirstjen Nielsen to serve as his next secretary of homeland security.

She is currently the White House principal deputy chief of staff.

Nielsen formerly served as John Kelly’s deputy when he held the post of Trump’s first homeland security secretary. She moved with Kelly to the White House when Trump tapped him as chief of staff in July, following a tumultuous period of staff infighting that spilled into public view with a series of high-profile departures.

The White House said Nielsen, who worked for the Transportation and Security Administration (TSA) under George W Bush, had “extensive professional experience in the areas of homeland security policy and strategy, cybersecurity, critical infrastructure and emergency management”.

Inside the White House, Kelly and Nielsen have sought to transform a chaotic West Wing into a more disciplined environment, pitting them at times against other senior aides competing for influence. Under their stewardship, according to one report, policy and planning meetings have been restricted to “principals only”, one of several moves designed to better control the flow of information to Trump and who has the president’s ear.



While that approach has earned its detractors in the White House, aides said Nielsen was known for a no-nonsense approach to the job that will probably serve her well in the Senate confirmation process.



But even as her nomination is not expected to be contentious, Nielsen will inherit a portfolio at the Department of Homeland Security (DHS) that is certain to attract tough questions from Democrats on Capitol Hill.



Many Senate Democrats expressed disappointment in Kelly for lining up behind some of Trump’s hardline immigration policies, such as his crackdown on undocumented people and so-called “sanctuary cities” and the travel ban on refugees and certain Muslim-majority countries.



It will be Nielsen’s task to shepherd the DHS as it oversees the phasing out of Barack Obama’s Deferred Action for Childhood Arrivals (Daca) program, which enabled hundreds of thousands of young, undocumented immigrants brought to the US as children to come out of the shadows and legally work and study without fear of deportation.



The DHS is also poised to implement Trump’s new travel ban, which revised the list of restricted countries and goes into effect on 18 October.



One of Nielsen’s most formidable challenges will arguably pertain to the investigation into Russian interference in the US election, which Trump has continued to blast as “fake news” despite the intelligence community’s assessment that Moscow took extensive measures to sway the 2016 election against Hillary Clinton.



The DHS is not only responsible for protecting against future such threats from foreign governments, but also said earlier this year it had evidence of attempts by Russia to breach election systems in 21 states. Last month, at least two of those states accused the agency of giving them bad information about Russian hacking.

Critics of the Trump administration were bracing for a more extreme pick to head the department responsible for fulfilling some of Trump’s core campaign promises. Among those who had been rumored as possible replacements were the former Milwaukee County sheriff David A Clarke Jr and the Kansas secretary of state, Kris Kobach, both known for harboring far-right views on immigration. Kobach caused a stir during the transition period when he arrived to a meeting with Trump, potentially for the DHS role that went to Kelly, holding a proposal for a Muslim registry.

