The bloody primary battles between Republican senators and tea party activists that have cost the party dearly for years aren’t materializing yet in 2016.

Headed into next year’s primary season, virtually none of the 22 GOP senators who are running for reelection have drawn viable challengers so far. At this point in past cycles, several prospective tea party candidates were already gathering steam, with outside groups preparing to spend millions in an effort to oust veteran incumbents.

The dearth of serious candidates has prompted leading conservative groups like the Club for Growth and Senate Conservatives Fund to focus instead on defending conservative Utah Sen. Mike Lee and backing candidates in open seats in Florida and Indiana, where Republican senators are not running for reelection. And neither group has plans to attempt to derail GOP senators in their primaries — at least not yet.

“We aren’t currently supporting any primary challengers, but we stand ready to do so if strong, viable candidates step forward,” Ken Cuccinelli, head of the Senate Conservatives Fund, said Tuesday.