Mitt Romney has opened his checkbook for just one Senate race this cycle: Arizona, where one of his leading campaign surrogates is fighting with one of his cousins for the GOP nomination.

It’s a delicate situation for the putative Republican presidential nominee, pitting his loyalty to a longtime supporter against his devotion to his family.

So Romney is betting on both horses.

In most years, Arizona would be far off the radar for the national GOP, too safe a red state over which to be worth losing sleep or campaign cash. But in 2012, Republicans are fending off a major challenge from a viable Democratic Senate candidate, and President Obama’s campaign has deemed Arizona in play in the presidential race as well.

Romney, who hasn’t donated his personal funds to candidates in any other Senate race so far this cycle, donated to Rep. Jeff FlakeJeffrey (Jeff) Lane FlakeOvernight Energy: Reporters barred from Day 2 of EPA summit | Dems blame Trump for gas price increases | Massachusetts to get new offshore wind farm Jeff Flake: Trump has 'debased' the presidency Senate Democrats look for traction on gas prices MORE (Ariz.), the GOP front-runner to replace retiring Sen. Jon Kyl (R-Ariz.). Flake has been a prominent surrogate for the former Massachusetts governor, joining him on the campaign trail in Arizona and Iowa and speaking on Romney’s behalf on a conference call with the national media.

Romney’s $2,500 donation came on Sept. 22, according to Federal Election Commission reports ­ — three days after Flake endorsed Romney in the presidential primary.

One month later, Romney donated the same sum to real estate mogul Wil Cardon, Flake’s primary opponent. Cardon’s father, also named Wil Cardon, is Romney’s second cousin.

All three Republicans are Mormons.

Romney hasn’t endorsed in Arizona — he has only weighed in on a few Senate races across the country — but Romney’s PAC, Free and Strong America, maxed out to Flake with a $5,000 donation in April.

Conversely, two of Romney’s sons have donated to Cardon and not to Flake. Matt Romney gave $500 in December, and Tagg Romney donated $5,000 in late March, FEC records show.

Tagg Romney is friends with Cardon, and the two attended Harvard Business School together in the 1990s.

Cardon served as Romney’s finance co-chairman in Arizona in 2008, but declined to endorse him during the 2012 primary, the Arizona Republic reported.

A Cardon aide told The Hill on Thursday that Cardon is now endorsing Romney and supports him as the GOP nominee.

The connections between Cardon and Romney date back multiple generations.

Romney’s father, former Michigan Gov. George Romney (R), was born in Colonia Dublán, a Mormon colony in the Mexican state of Chihuahua established in the late 19th century.

Cardon’s great-grandfather, Louis Paul Cardon, moved from Arizona to the same colony in 1897, according to genealogical records maintained by the Mormon Church and by Cardon’s family.

While in Mexico, one of his three wives gave birth to Wilford Pratt Cardon, the Senate candidate’s grandfather. The family later moved back to Arizona, where Wilford Pratt Cardon founded the company that his grandson now runs.

Cardon had been considered a long-shot candidate in the Senate primary, but has already injected more than $4 million of his own money into the campaign, spending most of it on television ads that have gone a long way to boost Cardon’s name recognition. A poll released Tuesday by Public Policy Polling showed that Flake’s 49-point lead over Cardon has shrunk to 22 points.

The winner of the GOP primary will face former U.S. Surgeon General Richard Carmona, a Hispanic veteran recruited by Obama and touted by Democrats as the rare candidate who can make Arizona competitive.

Romney’s campaign did not respond to an email asking whether the former governor will endorse in the GOP primary.

“I’m sure Romney just definitely does not want to see this thing devolve into a cow pie contest,” said an Arizona Republican strategist unaffiliated in the race. “Both come from long Mormon families. There are deep relationships throughout.”