WASHINGTON (AP) — Sen. Claire McCaskill endorsed an outside political group encouraging Hillary Rodham Clinton to run for president in 2016, saying it was important for Democrats to build a groundswell of support for the former secretary of state.

The Missouri Democrat’s support of the Ready for Hillary PAC on Tuesday marked the first time a member of Congress has endorsed the group. The organization does not have official ties to the former first lady, but it’s trying to lay the foundation for another Clinton campaign.