In a thinly veiled threat to congressional Republicans, President Obama on Tuesday warned the GOP not to obstruct a comprehensive immigration-reform bill now advancing in the Senate, ending his virtual silence on an issue paramount to his second-term agenda.

“If you’re actually serious and sincere about fixing a broken system, this is the vehicle to do it — and now is the time to get it done,” Obama said from the East Room of the White House. “There is no good reason to play procedural games or engage in obstruction just to block the best chance we’ve had in years to address this problem.”