The most important name that you haven’t heard much about in the Republican primary race is nonetheless a familiar one: Mike Huckabee, the former Arkansas governor who took the pageantry of presidential announcements to a nearly parodic level on Friday by appearing on national television to announce that he would announce whether he would run on May 5.

Mr. Huckabee may not be receiving much attention, but he is as important as any of the other second-tier candidates in the race, like Ted Cruz or Rand Paul. He has demonstrated appeal to a crucial bloc of Republican primary voters: the religious right. If he runs, he will be one of the most significant figures in the primary season, with the ability to deny a crucial segment of voters or even states to another candidate.

Whether he will run is perhaps the biggest outstanding question about the Republican primary field.

Mr. Huckabee is a Southern Baptist minister and a compelling politician with natural appeal to evangelical voters and cultural conservatives. In 2008, his support among evangelicals allowed him to carry Iowa and five primaries.

Early polls suggest he has retained at least some of that support in a far more competitive and conservative field. He’s averaging around 9 percent in national polls, putting him ahead of candidates like Mr. Cruz, Mr. Paul, Marco Rubio and Chris Christie. Unsurprisingly, Fox News, ABC/Washington Post and Quinnipiac surveys over the last month suggest that strength is being driven by evangelicals, who have offered Mr. Huckabee an average of 15 percent of their support.