WASHINGTON - Sen. Jeff Flake has purposely spent time on deserted islands, so being the sole Senate Republican weighing whether to back President Barack Obama on the international nuclear deal with Iran is hardly a new experience.
It might be uncomfortable, though.
As Congress heads off on its August recess ahead of next month's vote on the accord, the Arizona freshman is believed by Senate vote counters to be the only Republican who's truly undecided. His support for the agreement, which calls on Iran to curb its nuclear program in exchange for sanctions relief, is all Obama would need to call it bipartisan.
Republicans are generally uniform in their opposition, arguing that Iran cannot be trusted and a better deal should be brokered. A majority of Democrats will stand with the president, and are widely expected to muster the numbers to sustain any veto of a resolution of disapproval.
"On the whole, this agreement measured against the ideal doesn't look all that good," Flake said on the Senate floor Wednesday. "Against the alternative, it's a much closer call."
That position squeezes Flake between two powerful men who happened to be presidential rivals in 2008: Obama and Arizona Republican Sen. John McCain, now chairman of the Armed Services Committee.
For his part, Obama has launched a nearly daily lobbying effort in Congress to counter pro-Israel groups' well-funded barrage and Israeli Ambassador Ron Dermer's pleas. Obama incurred the ire of Republicans in his speech Wednesday when likened GOP lawmakers critical of the deal to Iranian fundamentalists.
"In fact, it's those hardliners who are most comfortable with the status quo," he said. "It's those hardliners chanting 'Death to America' who have been most opposed to the deal. They're making common cause with the Republican caucus."
The president's allies on Capitol Hill tried a more flattering approach.
"Jeff is as straight a shooter as there exists in this place," said Sen. Chris Murphy, D-Conn. "I don't know where Jeff will end up, but I know it will be because he's made a decision on the merits, not the politics."
Most Republicans, meanwhile, have made it abundantly clear that they won't support Obama, no matter how many briefings or gloves-off speeches.
But the 52-year-old Flake is in a class by himself.
From his election to the House in 2000, Flake bucked the Republican leadership by opposing special spending items called earmarks, which were later banned. He joined Democrats in support of the normalization of relations with Cuba, and supported a 2007 bill to ban workplace discrimination against gays. He was elected to the U.S. Senate in 2012.
The father of five also spent time on deserted islands in the Pacific Ocean - once by himself, once for a television show and once with his sons.
On Iran, Flake commended the administration for seeking a diplomatic solution to Iran's suspected march toward building nuclear bombs and said many of his questions have been answered. But he said he'll spend the August recess on remaining concerns, including Obama's willingness to crack down on Iran's misbehavior.
John McCain, meanwhile, made clear how he'd like his fellow Arizona senator to vote.
"Well, I always want him to vote the way I do," McCain said.