OMAHA, Neb. (AP) — Republican U.S. Rep. Jeff Fortenberry of Nebraska on Saturday resigned from office after a California jury convicted him of lying to federal authorities about an illegal campaign donation from a foreign national.

In a letter to the House, Fortenberry said he was resigning from Congress, effective March 31.

“It has been my honor to serve with you in the United States House of Representatives,” he said in the letter. “Due to the difficulties of my current circumstances, I can no longer effectively serve.”

Fortenberry’s resignation letter opened with a poem, “Do It Anyway,” that’s associated with fellow Catholic Mother Teresa. One line from the poem says: “What you spend years building, someone could destroy overnight. Build anyway.”

Fortenberry’s announcement followed concerted pressure from political leaders in Nebraska and Washington for him to step down. House Speaker Nancy Pelosi and House Minority Leader Kevin McCarthy on Friday urged Fortenberry to resign.

Nebraska Republican Gov. Pete Ricketts said Fortenberry should “do the right thing for his constituents” and leave the office he has held since 2005.

Fortenberry was indicted in October after authorities said he lied to FBI agents in two separate interviews about his knowledge of an illegal $30,000 contribution to his campaign from a foreign billionaire. Fortenberry was interviewed at his home in Lincoln, and then again with his lawyers present in Washington, D.C.

At trial, prosecutors presented recorded phone conversations in which Fortenberry was repeatedly warned that the contributions came from Gilbert Chagoury, a Nigerian billionaire of Lebanese descent. The donations were funneled through three strawmen at a 2016 fundraiser in Los Angeles.

Fortenberry’s withdrawal from the primary leaves state Sen. Mike Flood as the likely GOP nominee. The former speaker of the Nebraska Legislature, who has won endorsements from Ricketts and former Gov. Dave Heineman, has a strong advantage in the Republican-leaning 1st Congressional District. State Sen. Patty Pansing Brooks, a Democrat from Lincoln, is also running for the seat.

In a statement from his campaign, Flood thanked Fortenberry for “his many years of honorable service” and wished him and his family the best.

“Working together, we will keep this seat in Republican hands,” Flood said, promising to “continue the fight for our families, our economy and our conservative values in Congress.”

Pansing Brooks said Fortenberry’s conviction is a “wake-up call” that the district needs a change.

In a statement Saturday, Pansing Brooks said: “This opens the door for a new approach to serving (the 1st Congressional District). I am ready and able to meet that challenge and lead with integrity.”

The timing of Fortenberry’s resignation is expected to trigger a special election. Governors aren’t able to appoint a person to the seat.

Under Nebraska state law, the governor has to schedule a special election within 90 days once a congressional seat becomes vacant. Each political party gets to pick a nominee who will run to serve the remainder of the congressional member’s term.

Flood and Pansing Brooks will both run in the special election to fill the seat and run in November so they can serve the subsequent term.

Nebraska’s primary is May 10. Because counties have already mailed ballots to military members serving abroad and other absentee voters, it’s too late to remove Fortenberry’s name from the primary ballot. Election officials have said there isn’t time to schedule a special election to coincide with the primary.