JEFFERSON CITY, Mo. (AP) — Missouri Attorney General Josh Hawley is taking a first step toward entering the race for U.S. Senate.

Hawley spokesman Scott Paradise on Wednesday confirmed the Republican will launch an exploratory committee this week for a possible challenge to Democratic U.S. Sen. Claire McCaskill.

Big-name Missouri Republicans and donors coalesced around Hawley as a favored candidate to challenge McCaskill. She’s among 10 Senate Democrats running in states won by President Donald Trump. An exploratory committee will allow Hawley to start raising money for a bid before he announces a final decision.

While he had close to $1 million in his state campaign coffers at the end of June from his 2016 race for attorney general, he can’t use that money on a federal race.

McCaskill is considered one of the most vulnerable Democrats in the 2018 election.