The ad has $250,000 behind it and will run through Sunday nationally, and calls for a pathway to citizenship for immigrants who entered the country illegally.

Labor unions are a major force in favor of immigration reform, though tensions over a future guest-worker program Republicans and business groups see as a must-have could complicate the debate over the bill.

"Last November, Washington understood the growing power of Latino voters," the ad's narrator says in Spanish. "We registered, we voted, we made a difference. And leaders from both parties pledged to create common-sense immigration reform with a fair, reasonable and timely path to citizenship. Now, members of Congress are working together, developing bipartisan plans for immigration reform."

The ad warns that "there are some in Congress who reject this bipartisan proposal."

"They want to deny millions of hardworking Latinos a path to citizenship, keeping millions of Latino families in a state of uncertainty about whether they might still be separated," the ad continues. "But the power to make a difference is ours. They heard our voice in November — they'll hear it again today."