JEFFERSON CITY, Mo. (AP) – Missouri residents hoping to vote in next month’s presidential primary are running out of time to register.

The secretary of state’s office says people must register by Wednesday to be eligible to vote in the Feb. 7 primary, which also includes a vote on Buchanan County’s five-year CIP sales tax question.

For those not registering in person, a registration card must be postmarked Wednesday at the latest. Voters whose addresses are unchanged don’t need to register again.

Missouri’s primary will serve as a public opinion poll for the GOP candidates seeking to challenge Democratic President Barack Obama.

That’s because the state Republican Party has opted to use a caucus system that starts in March to award delegates to the national convention at which the GOP nominee will be officially selected.