The campaign trail in Iowa this week might look a little familiar: As Mitt Romney and Texas Gov. Rick Perry stump around the state, former Sen. Rick Santorum’s face is plastered on the local airwaves.  

The 2012 presidential primary is long gone, but a couple of the GOP’s future presidential hopefuls are using the Senate primary in the crucial nominating state to their advantage.  

Sen. Marco Rubio, R-Fla., has backed the GOP front-runner, state Sen. Joni Ernst. Romney, who is not expected to run in 2016, has also given her his support. Meanwhile, Perry has endorsed former District Attorney Matt Whitaker. Santorum is supporting radio host Sam Clovis. A fourth candidate in the race, former energy executive Mark Jacobs, does not have any endorsements from likely presidential candidates.  

The contest marks a rare opportunity for 2016 hopefuls: There hasn’t been an open-seat Senate race in the Hawkeye State in three decades. By backing a Senate candidate, presidential prospects can cement relationships with them and their staff that could be valuable next cycle — no matter if their chosen Republican wins or loses.  

“The caucuses are an activist-driven process and activists put a premium on who stands with them,” said Republican radio host Steve Deace, who has endorsed Clovis.  

“After all,” he added, “if you’re going to ask activists to stand with you, they’ll want to know if you stood with them.” In Iowa, relationships from past campaigns loom large in endorsement decisions. Clovis supported Santorum; Whitaker backed Perry’s campaign; and Ernst supported Romney in both his presidential campaigns.  

“Iowans appreciate loyalty,” said former Iowa Republican Party Chairman Matt Strawn, who called their allegiances “admirable.”  

These kinds of endorsements won’t “lock up a large block of supporters” for 2016, said Republican consultant Bob Haus, who worked for Perry. But not backing the officials and activists who backed them could send a bad message to potential supporters down the line, he said.  

For someone like Rubio, who does not have any favors to return from a previous campaign, the endorsement offers a chance to start building those relationships.  

“It is smart politics in that it allows his team to start developing key Iowa contacts without the breathless Inside the Beltway 2016 speculation headlines that would occur if the Senator himself set foot in the state or was otherwise directly and personally interacting with key Iowa activists,” Strawn emailed.  

Perry tried to tamp down that speculation at an event with Whitaker on Wednesday, telling The Associated Press that the appearance “had everything do to with Matt Whitaker,” not the makings of another presidential bid. But he used the visit to put in plenty of face time with activists and voters, first stumping with Whitaker at a manufacturing shop in Hiawatha, Iowa, and later at several events with Gov. Terry E. Branstad.  

Romney made a couple stops with Ernst on Friday — his first appearance in the state since his failed presidential bid two years ago. He touted her as a “real Iowan,” the Des Moines Register reported, and a good choice for Senate, to a friendly crowd.  

Both appearances drew buzz and media attention for the Senate candidates in the final days of the race.  

The Iowa Republican primary is June 3. If no candidate gets over 35 percent of the vote, the nominee will be decided by convention on June 14.  

The race is rated Leans Democratic  by the Rothenberg Political Report/Roll Call.