On Monday, Sen. Patrick Leahy (D-Vt.), chairman of the Senate Judiciary Committee, accused his GOP colleagues of trying to ‘exploit’ last week’s Boston bombings to delay immigration reform. (The Washington Post)

Democratic lawmakers accused Republicans on Monday of trying to “exploit” the Boston Marathon bombings for political gain, revealing divisions that could complicate prospects for a bipartisan effort to overhaul the nation’s immigration system.

During a Senate Judiciary Committee hearing that turned testy at times, Chairman Patrick J. Leahy (D-Vt.) chastised some of his GOP colleagues for tying last week’s attack to the debate over a comprehensive immigration bill that was introduced last week.

The two bombing suspects, Dzhokhar and Tamerlan Tsarnaev, were members of an ethnic Chechen family that received asylum in 2002 under U.S. immigration law, prompting many Republicans to urge caution on border-control reform.

“Last week, opponents began to exploit the Boston Marathon bombing,” Leahy said during his opening remarks on the 844-page bill. “I urge restraint in that regard. Refugees and asylum-seekers have enriched the fabric of this country from our founding. . . . Let no one be so cruel as to use these heinous acts of two young men last week to derail the dreams and futures of millions of hardworking people.”

Sitting next to Leahy, Sen. Charles E. Grassley (R-Iowa) responded to the chairman by comparing the GOP concerns to the push by Democrats for greater gun control after the mass shooting at an elementary school in Newtown, Conn., in December.

“When you proposed gun legislation, we did not accuse you of using the Newtown killings as an excuse,” Grassley said. “I think we’re taking advantage of an opportunity — when once in 25 years we deal with immigration — to make sure every base is covered.”

While the hearing was underway, Republican Sens. Rand Paul (Ky.) and Marco Rubio (Fla.), a co-sponsor of the immigration bill, issued separate statements calling on lawmakers to take time to learn whether U.S. immigration laws did not properly vet the Tsarnaev family before granting asylum protections.

Rubio, who did not attend the hearing, said he disagreed with Leahy that Boston was not relevant to the debate. He said that the bill would improve border security but that “Congress needs time to conduct more hearings and investigate how our immigration and national security systems could be improved going forward. The attack reinforces why immigration reform should be a lengthy, open and transparent process.”

Proponents of immigration reform fear that critics will use legislative delays to lengthen the debate and introduce amendments aimed at killing the agreement, which features a path to citizenship for most of the nation’s 11 million illegal immigrants. A similar strategy helped doom a bipartisan immigration bill in the Senate in 2007.

At the White House, press secretary Jay Carney said President Obama thinks lawmakers should move forward without delay.

“We need to bring out of the shadows the roughly 11 million residents of this country who are here illegally,” Carney said. “The process of moving along the earned path to citizenship, and the various hurdles that have to be cleared in that process, allows for much more information to be known by the relevant authorities and agencies about these individuals, and that’s very important.”

Dozens of advocates packed the hearing room Monday, wearing T-shirts reading “Protect the Path” and “Keep Families Together.” The immigration bill also includes increased federal funding for new border surveillance drones, fencing and customs agents; new visa programs for low- and highly skilled workers; and fewer visas for extended family members trying to reunite with relatives in the United States.

Nearly two dozen people testified at the seven-hour hearing, including Kansas Secretary of State Kris Kobach, who in 2010 helped Arizona craft one of the nation’s strictest immigration laws. Three of the four provisions of that legislation were later struck down by the Supreme Court.

Sen. Ted Cruz (R-Tex.) said he would support stronger border control and fixes to the legal system regarding immigration, but he predicted that including a path to citizenship for the undocumented would doom the bill.

“I don’t think that there is any issue in this entire debate that is more divisive,” he said.

Leahy announced that Homeland Security Secretary Janet Napolitano, who canceled her scheduled appearance before the Judiciary Committee on Friday to deal with the Boston bombing manhunt, will testify on Tuesday. Leahy has said he hopes to take amendments on the bill in early May and send it to the full Senate by early June.

But many leading Republicans have argued that Democrats are rushing the process. In his letter to Leahy, Paul cited the Boston attack+ to argue that “we should not proceed until we understand the specific failures of our immigration system.”

Paul asked why the suspects’ family was allowed to remain in the United States after coming from Chechnya, “an area known as the hotbed of Islamic extremism.” U.S. officials have said the Tsarnaevs are an ethnic Chechen family who legally immigrated from Dagestan, a neighboring Russian region, about a decade ago.

Later in the hearing, Sen. Charles E. Schumer (D-N.Y.), a co-sponsor of the bill, told colleagues that it is unfair for “those pointing to the terrible tragedy in Boston” to use the bombings “as an excuse to wait many months or years.”

Grassley cut him off by responding loudly, “I never said that.”

Leahy banged his gavel twice to restore order. Schumer resumed his remarks by assuring Grassley that he was not referring to any of the lawmakers in the room.

Discuss this topic and other political issues in the politics discussion forums.