WASHINGTON -- Sen. Lindsey Graham, Republican of South Carolina, is a jovial sort, but he was scowling like a man who'd just discovered that he might have boarded the wrong bus.
"How do we put together a bill and then the guy who put it together says that he may not vote for it?" Graham asked me. "I just don't get what we're doing here."
His specific complaint: that GOP Sen. Marco Rubio of Florida, a fellow member of the Senate "gang of eight" who had spent months drafting a bipartisan immigration reform bill, seemed to be backing away from the legislation.
Rubio said that its border enforcement provisions need to be strengthened -- and that he might oppose the bill if he didn't get strong enough revised language. This infuriated and exasperated Graham, who had joined the gang in the first place to try to do a good legislative deed and also to protect himself politically.
Graham is the human fault line of Republican national politics. He is a conservative who represents a ruby-red state and still might face a tea party primary challenge next year, an inside dealmaker who thinks that the GOP will enter a demographic "death spiral" if it doesn't quickly figure out a way to appeal to Hispanics and take the immigration issue away from the Democrats.
Graham needed Rubio to bless the deal and stick with it, not flinch at the first whiff of tea party gunpowder.
The truth is that the immigration issue is getting bollixed up in 2016 GOP presidential politics. Other young Republican bucks didn't like Rubio arrogating the issue to himself, especially since he (like they) is a Senate novice.
It took all of five minutes for Sen. Rand Paul of Kentucky to move to Rubio's right, demanding much stronger border security measures. Paul's staff told me that he's hoping for a vote on his amendment later this week. The bet here is that Rubio will support it. So, presumably, will Graham.
Senate supporters are still aiming to somehow gather 70 votes for passage of the full 800-page bill, but since they are likely to lose a couple of Democrats, that means roping in 20 or so GOP votes.
As of now, that seems unlikely, which means that Graham may be stuck on the bus headed for the worst of all worlds: support of a bill that was deemed too soft by a key author and couldn't win enough votes to pass Congress.