JEFFERSON CITY, Mo. (AP) — Four former Republican U.S. senators from Missouri are urging Attorney General Josh Hawley to run for Senate.

Former Sens. John Ashcroft, Kit Bond, John Danforth and Jim Talent asked Hawley to enter the race in a public letter dated Thursday.

Hawley hasn't said whether he'll vie for Democratic U.S. Sen. Claire McCaskill's seat in 2018. But he's facing pressure from big-name Missouri Republicans and donors to run.

McCaskill is among 10 Senate Democrats running in states won by President Donald Trump, making the Missouri seat vulnerable.

Danforth has pushed Hawley to enter the race for months. He and the other former U.S. senators said in the letter the Senate is now "dysfunctional" and that Hawley could help end that problem. They also tout his background in constitutional law.