Broun is the only announced member running in the race to succeed Chambliss. But some GOP operatives worry he is too conservative to win in the general.
Finally, whether and who powerful and well-monied outside groups, such as the anti-tax Club for Growth, support could be a determining factor in the Senate race.
At the end of 2011, the most recent year for which data are available, Broun, Graves and Price all had lifetime scores of 95 percent or more with the Club for Growth.
Gingrey had 85 percent and Kingston had 82 percent.
Barney Keller, a spokesman for the Club for Growth, said, “We’re watching the race.”
As are a lot of people.
The field remains extremely fluid, and many more candidates could jump in.
Along with federal and current and former statewide officials, “you’ve got maybe a dozen lesser-known names who are toying with it,” said Perdue, the GOP consultant. “Every time the tide comes in, it seems to wash something else up.”
An earlier version of this story misstated the location of Broun's district. It is east of Atlanta.
Terri Henderson, 6, center, whose mother is El Salvador, attends a rally with members of Congress at Union Station's Columbus Circle to announce the Restore Opportunity, Strengthen, and Improve the Economy (ROSIE) Act on July 29, 2014. The legislation provides incentives for government contractors to pay a living wage and other benefits that would help low-income workers.