Crossroads GPS is spending $100,000 on print ads in Beltway publications promoting immigration reform. (Watch video)

The ads from the Republican ally call a bipartisan Senate bill to be debated on the floor this week an "important starting point" to fixing immigration, though the group calls for tighter border enforcement.

"The Senate immigration bill needs an 'extreme makeover' before we can say it really protects our borders and our workers, but it's important that Congress move forward on it and not just throw up its hands," said Crossroads GPS CEO Steven Law. "This isn't just about politics; it's about taking responsibility for solving a critical national problem."


Law also warned that if Congress doesn't act with Republican cooperation, President Obama could move immigration reform to the left.  

"If we lose this opportunity to pass meaningful immigration reform, we will give President Obama an opening to shift immigration policy further to the left by executive fiat," Law said.

The campaign, with print ads in four D.C. publications including The Hill as well as targeted online ads, comes at a crucial time for immigration reform. The full Senate just began debate on a comprehensive reform bill, while House Republicans are still grappling with how to handle the issue. 

The ad has the signatures of more than 50 GOP leaders, conservative economists and business leaders. 

The list includes a number of Republicans who've long backed reform, like former Florida Gov. Jeb Bush (R), former Sen. Norm Coleman (R-Minn.), and GOP strategists Karl Rove and Ed Gillespie, as well as some others who haven't been as publicly involved in the issue, like former Puerto Rico Gov. Luis Fortuño (R), former Rep. Francisco Canseco (R-Texas), and former Sen. Phil Gramm (R-Texas).

Some recent developments are making pro-reform advocates nervous: Sen. Marco RubioMarco Antonio RubioRubio blocks quick votes on stalemated defense bill Wisconsinites need infrastructure that is built to last  Republicans struggle to save funding for Trump's border wall MORE (R-Fla.) has continued to push for border enforcement measures, frustrating some Democrats, while Rep. Raúl Labrador (R-Idaho), one of the original House Gang of Eight working on a comprehensive deal, left the group last week. This week could prove a crucial test for whether the bill has enough support to pass in the Senate and spur the House to act.