WASHINGTON » These are hectic days for the federal deportation officer who has made it his single-minded mission to stop a bipartisan bill to overhaul the immigration system that is making its way through the Senate.

The officer, Chris Crane, heads the union of immigration enforcement agents. Obama administration officials become exasperated at the mere mention of his name.

Recently, Crane testified about the bill in the House Judiciary Committee, securing his record as the most frequent witness on Capitol Hill during this year’s immigration debate and the favorite expert of conservative critics of the Senate measure. Once again, his warnings were categorical and dire.

"Americans should understand that this legislation only guarantees legal status for illegal aliens, including serious criminals," Crane said. "It contains no promise of solving our nation’s immigration problems."

Crane also sat down with Sen. Marco Rubio, R-Fla., who helped write the bill, offering a sweeping critique of its security provisions. Then, Crane starred at the news conference where Rep. John Barrow, D-Ga., presented his alternative bill on enforcement, which reflected many of Crane’s demands for more immigration agents and less leeway for administration officials to decide how to deploy them.

And the pace is picking up for Crane, even though his union, the National Immigration and Customs Enforcement Council, represents 7,700 of 20,000 employees of the immigration agency known as ICE.

After the Senate bill survived a barrage of hostile amendments in committee, it is headed to the full Senate with momentum that has surprised even its supporters, driven by a coalition including Latinos, high-tech businesses, growers, labor federations and religious groups. It would create a 13-year path to citizenship for immigrants here illegally, strengthen border security and revamp legal immigration.

Opponents, playing defense, increasingly argue that the bill is weak on enforcement, and would allow a new wave of illegal immigration. Crane is the go-to guy to make that case.

He says, in stark terms, that the Obama administration’s performance could not be worse.

"Across the board, we’re not doing law enforcement work," Crane said in a recent interview in Salt Lake City, where he is based. "It’s very disturbing as an employee in general to see the Department of Homeland Security lie to the American people day in and day out about who we’re arresting."

He claims that officials with Immigration and Customs Enforcement have exposed agents to danger from gang members in detention centers, and that they threatened to discipline agents for detaining illegal immigrants encountered on the street. To reinforce his points, he brought a lawsuit last year against Janet Napolitano, the secretary of homeland security. A decision from the Texas judge in that case is expected soon.

Homeland Security officials said their enforcement record speaks for itself. Under the Obama administration, ICE has deported more than 1.4 million people, including increasing numbers of convicted criminals – 225,000 last year. Officials say Crane ignores the deportation numbers as part of a personal crusade to put a right-wing tilt on immigration policy, which they say is out of line with his duties as a law enforcement officer.

Plain-spoken and camera-shy, Crane is an unlikely labor firebrand.

He said he had grown up in conservative country in Wyoming and served two tours in the Marine Corps before joining ICE 10 years ago. He traced his bitter doubts about the agency to his early days there, when, he said, his first supervisor was frequently drunk on the job. He joined the union for protection from retaliation after he reported that manager, he said.

Since then, morale among ICE employees has been sinking, he said, with Homeland Security ranking 279 out of 292 federal agencies in an annual federal government survey last year.

"Our managers are completely out of control," Crane said. He recalled an episode in 2009 in an ICE office in El Paso, Texas, when two married agents said their baby had been born with medical problems because of work pressure and sexual harassment during the pregnancy.

ICE agents protested on the female agent’s behalf, Crane said. He broke into tears as he recounted the events.

More recently, his feud with top ICE officials is over a policy instructing deportation officers to exercise prosecutorial discretion, deporting criminals rather than immigrants whose only violation is being here illegally. Crane said many ICE agents found the policy, which was started two years ago, confusing and contrary to their mission. He waged a battle with ICE managers over when and how agents would be trained to carry it out.

"They are asking law enforcement officers to basically ignore their law books," Crane said. "For officers out in the field, we can’t function like that. We have to have laws that are very clear, that aren’t ambiguous, that we can confidently go out into the street and enforce."

ICE officials strongly disputed many of Crane’s statements. Brian Hale, an ICE spokesman, said that the episode in El Paso had been swiftly referred to the agency’s inspector general, and that top managers there had changed.

"Any suggestion that this allegation of local misconduct is in any way linked to the broader policy disagreements between the union and ICE management is incorrect and misleading," he said.

Crane is in a minority in the immigration agency. Nearly 9,000 investigating agents in ICE are represented by a different organization, the Federal Law Enforcement Officers Association, and they do not agree with his approach.

"The union has a tendency to fire Scud missiles at the administration," said Andrew Rakowsky, the association’s representative at ICE. "We work to find common ground."

And Crane is in an even smaller minority among law enforcement leaders, with national associations of police chiefs and sheriffs rallying behind the White House to support the bill. He is also rowing against a flood tide in the labor movement, even though his local is affiliated with the AFL-CIO. The federation has organized a nationwide campaign to push for the overhaul. Its leaders have also called on the Obama administration to halt almost all deportations while the legislation is being debated.

© 2013 The New York Times Company