Aguilar singled out the Federation for American Immigration Reform for pushing agendas that he said don't line up with either the Republican Party or the Catholic Church.
"They believe in zero-population growth," he said. "They believe immigrants contribute to global warming. Since when was that a conservative issue?"
He noted FAIR was founded by John Tanton, who worked several years with Michigan-based Planned Parenthood chapters and wrote extensively about the positive aspects of birth control.
Catholic Church teachings prohibit the use of contraception among its members and also forbid abortions.
But FAIR spokesman Ira Mehlman said his organization isn't partisan and that supporting tighter immigration policies is in the best interest of the country roughly allowing 300,000 people a year into the country.
"Our interest is in the future of the United States, not the Republican or Democratic parties," Mehlman said. "There is no direct correlation between immigration and economic growth and prosperity. There are all sorts of facets that go into the equation."
FAIR was in the headlines recently when Kansas Secretary of State Kris Kobach announced his support for GOP presidential hopeful Mitt Romney. Kobach is an attorney with the Immigration Reform Law Center, the legal arm for FAIR that has helped craft and defend a series of tough enforcement-only immigration measures ranging from Arizona's SB1070 law to a similar measure in South Carolina.
Kobach also is a supporter of eliminating the birthright citizenship clause of the 14th Amendment of the U.S. Constitution and has assisted states' attempts to pass laws that remove birthright citizenship.
Aguilar called Romney's effusive comments about the Kobach endorsement "mind-boggling."
But while Aguilar worried about the toll strident anti-illegal immigration activists were having on the Republican Party, he also cautioned that President Barack Obama remains vulnerable on the issue.
He said the president made it a top priority to engage in comprehensive immigration reform when elected in 2008 and said that with a Democratic majority in Congress, he didn't accomplish anything close to that.
"There have been unfulfilled promises," he said.
Ari Noorani, executive director of the National Immigration Forum, said the vacuum has left states to try to craft legislation and he praised Utah for its development of The Utah Compact which resulted in a series of immigration bills signed into law by Gov. Gary Herbert, including a highly controversial guest-worker law that is the subject of a repeal and replace movement.
On Thursday, State Rep. Chris Herrod, R-Provo, shared with The Salt Lake Tribune his proposal to replace HB116. Among its key provisions is a proposal to remove the start date of July 2013 currently written into the law and instead require permission of Congress for the bill to take effect.
And while HB116 would levy fines against undocumented immigrants working in the state, Herrod's proposal also fines them with the funds going to a pool for restitution for identity theft victims. The difference, Herrod said, is that his legislation would require them to leave the country.
"I think the bill aligns with the Republican Party platform," Herrod said.
It also allows non-working spouses to apply for a marriage visa and to stay in the state under the premise they have committed only a civil infraction. He said the bill provides compassion sought by The Utah Compact and it aims to keep families together a chief concern for the Conference of Bishops.
The conference meeting concludes Friday with a panel featuring representatives from the U.S. Department of Homeland Security.