This article is from the archive of our partner National Journal

The conservative groups that brought down Senate incumbents and other moderate Republicans running for office in 2010 and 2012 primaries had relatively little success in 2014. But the next election comes with an opportunity to take a second swing at a big nemesis, one who stands apart from any other Republican senators up for reelection in 2016, according to interviews with conservative strategists.

"If you're making a list, there's two lists," said Daniel Horowitz, the senior editor at Conservative Review, a new conservative research group. "There's John McCain, and then there's the rest. John McCain is a category of his own."

"If he winds up running and winning reelection, then primary challenges are dead," Horowitz said.

McCain, who will be 80 in 2016, has not definitively said he's running for reelection, but the five-term senator has hinted it multiple times and spoken with donors about his prospects. The Armed Services Committee chairman-in-waiting was a target of conservatives in 2010, when he defeated former Rep. J.D. Hayworth by more than 20 percentage points. But four years and one Gang of Eight immigration bill later, conservatives have made him their ultimate target once again.

"Definitely number one is going to be John McCain. That shouldn't be a surprise to anybody," said one conservative group's political director.

A big part of the reason why is that elsewhere across the 2016 map, it's looking like slim pickings for conservatives. These groups tend to prefer playing in safe, red states where opponents of their candidates can't rebut with an electability argument about winning the general election. Given the blue hue of the 2016 Senate map, a number of more moderate Republicans may get some protection from that. Others have wised up to the mistakes of their colleagues and gotten out of the gate early to raise money and rally support within the GOP.

"Honestly, I think it's going to be a relatively small map," said one conservative strategist who asked not to be named. "But in the end, it may wind up playing better into conservatives' hands, in that you may see a better concentration of funding and resources and bodies on the ground in just a few states instead of a lot of states."

Horowitz noted that McCain is conservatives' first shot at a second chance, a test balloon for whether you can "slow bleed" an incumbent over multiple election cycles. After losing the 2008 presidential race, McCain tacked to the right in 2009 and 2010 before his challenge from Hayworth. The maneuvering included a memorable TV ad in which McCain said he would "complete the danged fence" along Arizona's border with Mexico. But his cosponsorship of the Senate's comprehensive immigration reform bill will be fresher in conservatives' minds, among other recent actions.

Horowitz predicts McCain will play up some of the things he's good on with conservatives, such as ag-trade subsidies and earmarks. "But try putting that up against immigration, cap and trade, and the Bush tax cuts," said Horowitz, adding that McCain was "waving a red flag in front of the bull" with conservatives.

Reps. Matt Salmon and David Schweikert are two high-profile potential recruits that conservatives have been eyeing for some time; back in April, Citizens United Political Victory Fund released a robopoll showing McCain trailing both congressmen—and behind Salmon by double-digits—in hypothetical matchups. Schweikert, for his part, has already said he would "weigh his options" over the holidays and look to polling numbers for guidance.

Conservatives' next tier of targets after McCain begins with Georgia's Johnny Isakson, who announced his bid for reelection just weeks after the 2014 cycle concluded. But early reports indicate Isakson has already moved to undercut any anti-incumbent effort. He's banked $2.25 million for his campaign fund, and he reached out to fellow members of his delegation months ago to pull them on board with his campaign.

Down from Isakson, the rest of the map gets a bit hazy. Conservatives would love to take another crack at Sen. Lisa Murkowski of Alaska, who lost to their favored candidate, Joe Miller, in the 2010 primary but came back to retain her seat in a write-in campaign. They believe her position as the incoming Energy Committee chair might give them some additional fuel depending on how the legislative session plays out, but finding a challenger may prove difficult, and Miller's latest Senate run this year ended in the GOP primary.

Sen. Jerry Moran of Kansas made some conservative enemies as chairman of the National Republican Senatorial Committee, which intervened on behalf of establishment candidates in primaries under his leadership this past election year. Some claim radiologist Milton Wolf, who held Sen. Pat Roberts to less than 50 percent of the vote in his 2014 primary, might try his hand again, and Rep. Tim Huelskamp has said he wouldn't rule out a run. But Moran's NRSC tenure has also won him plenty of cred.

Conservatives admit Moran's neighboring senator, Missouri's Roy Blunt, is a "formidable campaigner," while Alabama's Richard Shelby has an intimidating amount of cash stockpiled for his race—more than $18 million.

Meanwhile, as some conservative groups survey the landscape looking for incumbents to topple, one notable organization is sitting back and waiting for things to develop a bit more. The Club for Growth has so far endorsed six senators for reelection in 2016: Marco Rubio of Florida, Rand Paul of Kentucky, Pat Toomey of Pennsylvania, Tim Scott of South Carolina, Mike Lee of Utah, and Ron Johnson of Wisconsin. The group declined to name any incumbents it plans to target this cycle.

"Our standard for supporting or opposing a candidate for federal office is pretty well known at this point," spokesman Barney Keller said in an email. "If a pro-growth conservative runs for office, we consider supporting him or her through our PAC."

The Club's focus on endorsements versus challenges underlines an important factor in looking ahead to conservative battlegrounds: Often, the competitive slate of primary challenges is determined by the availability of candidates, not necessarily the vulnerability of the incumbent. An early-2013 target list for the 2014 cycle might have included Sen. Lindsey Graham, for example, but he went on to win the South Carolina primary by a wide margin (though he did capture only 56 percent of the vote). And an early list would likely not have included Sen. Thad Cochran, whose Club for Growth-fueled primary in Mississippi went into a runoff that Cochran won by fewer than 8,000 votes. Opponent Chris McDaniel never conceded.

That makes it too early to declare any one primary a certainty or foreclose on competition for the GOP nomination in other states with an incumbent senator. But at this starting point, a number of conservative strategists at least agree on what looks promising right now. "Arizona will be the epic battle," said Horowitz.

This article is from the archive of our partner National Journal.

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