Sen. Marco Rubio broke Thursday with the rest of the Gang of Eight that wrote the immigration bill, voting to back a strict border security amendment that would have imposed real yardsticks for any eventual path to citizenship for illegal immigrants.
The border security amendment failed anyway, overwhelmed by Democratic opposition. But the vote marks the first time that the eight senators who wrote the immigration bill — four Republicans and four Democrats — haven’t voted in lock-step on a major potential change to the bill.
A bigger border security test is still to come on another deal that is being written Thursday afternoon.
On the Senate floor, those involved in writing the agreement were generally all smiles as they explained their agreement to colleagues.
But at one point Mr. Rubio huddled with Sen. Charles E. Schumer, the New York Democrat who’s taken the lead on writing the main bill, and Sen. Robert Menendez, New Jersey Democrat and another member of the Gang of Eight, to talk about what Mr. Schumer was overheard calling “the fence thing.”
“He just wants to make sure it’s doable,” Mr. Schumer said.
The deal they are working on reportedly involves doubling the size of the border patrol and building more fencing along the border before illegal immigrants get eventual citizenship. They would still get quick temporary legal status and work permits no matter what.
Mr. Rubio’s vote Thursday angered immigrant-rights groups.
“Whose side is Senator Rubio on?” said the Dream Action Coalition, a group of illegal immigrants who got legal status under President Obama’s non-deportation policies.
The coalition said it will run ads urging Mr. Rubio to stick with the deal and to forgo other changes he’s said he’ll seek, including pushing for immigrants to prove they’ve learned English in order to earn green cards.