Rep. Ralph Hall (R-Tex.) was forced into a GOP runoff election Tuesday, putting in jeopardy the political future of the oldest member of Congress.

Hall, 90, led the way with 45 percent of the vote against former U.S. attorney John Ratcliffe in the primary with about a quarter of precincts reporting. But that fell short of the majority needed to avoid a May runoff under Texas election law. The Associated Press called the race a runoff Tuesday evening.

Hall is one of two World War II veterans left in Congress and the only member running for another term. The other is Rep. John Dingell (D-Mich.), the longest-serving member of Congress in history. He is retiring at the end of this term.

Ratcliffe is wealthy and self-funded his campaign.