Updated as of 2:27 p.m.

The special election that will determine who takes Rep. Mike Pompeo’s seat will be trigger when the Kansas Republican officially resigns after he was selected on Friday by President-elect Donald Trump to head the CIA.

The timing of the election must fall between 45 and 60 days after the resignation. Kansas Republican Gov. Sam Brownback has five days from the day Pompeo submits his resignation to set the date of the election.

Pompeo’s seat became the first in the House to be up for special election next year.

State Treasurer Ron Estes is a leading contender for the GOP nomination. He formed an exploratory committee for a congressional bid when Pompeo considered challenging Sen. Jerry Moran in a primary earlier this year.

The district committees for the Republican and Democratic parties will hold a convention to select their nominees. Individuals can also get on the ballot as independents if they collect signatures from 4 percent of all voters in the 4th District, located in the southeast corner of the state.

Pompeo’s re-election race this year was rated Safe Republican by The Rothenberg & Gonzales Political Report/Roll Call. He ended up winning by 32 points. Mitt Romney carried the district by 26 points in 2012.

Pompeo, who serves on the House Intelligence and Benghazi committees, was an executive in the aerospace and oil industries before his election to Congress in 2010. A West Point and Harvard Law graduate, he served in the Army from 1986 to 1991 as a tank commander in Germany toward the end of the Cold War.

“He will be a brilliant and unrelenting leader for our intelligence community to ensure the safety of Americans and our allies,” Trump said in a statement.

Former CIA Director Michael Hayden said he was “heartened” by Trump’s choice of Pompeo.

“I think this is a serious man who takes these questions seriously and has studied these questions,” Hayden said.

Pompeo was among a host of Republicans who blasted Hillary Clinton, Trump’s Democratic rival in the presidential campaign, over her use of a private email server while she served as secretary of State.

In Congress, he has championed a number of conservative causes, including eliminating tax breaks for energy companies. His district includes Wichita, home to Koch Industries, a conglomerate whose owners give millions to conservative causes and politicians.

Many liberals view the Koch brothers with suspicion, prodding Pompeo, a recipient of Koch campaign donations, to defend them.

Simone Pathé contributed to this report.Contact Rahman at remarahman@cqrollcall.com or follow her on Twitter at @remawriter.