A key Senate race is beginning to take shape in Missouri.

Fox's Jared Halpern has more from Capitol Hill:

Missouri's Republican Attorney General Josh Hawley will run for Senate next year challenging Democrat Claire McCaskill.

McCaskill is one of 10 Senate Democrats running for re-election in a state won by President Trump last year.

Hawley is 37-years-old and serving his first year in elected office. In a video announcement, he says he did not plan on a Senate run, but believes we have to do all what we can to win a better future.

Missouri Democrats have expected Hawley to enter the race, for months accusing him of using the attorney general's office as a political stepping stone.

On Capitol Hill, Jared Halpern, FOX News.

Follow Jared Halpern on Twitter: @JaredHalpern