Iowa Congressman Dave Loebsack has announced he will not seek reelection in 2020.

In a written statement, Loebsack said he had intended to retire after winning reelection in 2016. But after Donald Trump won the presidency, Loebsack was the only Democrat left in Iowa’s congressional delegation and he decided to run for a seventh in 2018. Loebsack, who is 66 years old, easily won last November by a 12 percent margin.

With Loebsack’s announcement, Iowa’s congressional races in 2020 are shaping up to be among the nation’s most-closely-watched. First-term Congresswomen Abby Finkenauer of Dubuque and Cindy Axne of West Des Moines will be seeking second terms. Republican Congressman Steve King, the dean of Iowa’s House delegation, faces primary challengers in his bid for a 10th term.