President Obama’s executive action sparing millions of illegal immigrants from deportation will be the biggest federal program rollout since ObamaCare -- and administration officials are hoping its launch, set for May, will be a lot smoother.

“The deputy secretary and I are very focused on this, and I believe we're going to get it right,” Department of Homeland Security Secretary Jeh Johnson told Fox News on Thursday.

Still, Republican opposition to the plan that would block deportation of as many as 5 million illegal immigrants -- most of them parents of children already here legally -- is nearly as intense.

DHS has leased a massive office building in Crystal City, Virginia, just across the Potomac River from Washington, where a thousand federal workers and a thousand more contractors will process applications. Though forecasting turn-out of applicants is largely a guessing game, DHS predicts as many as 1.3 million people may apply in the first six months alone.

The Crystal City office demonstrates to critics just one of many problems with the President’s executive action. "Those employees are not going to ask people from all over the country to come to Crystal City to be interviewed. They're not going to be effectively interviewed. They’re going to do online most of their work," said Senator Jeff Sessions, R-Ala.  He believes the online interview process is a recipe for fraud. 

There's also the cost of the plan -- officially known as Deferred Action for Parents of Americans  -- estimated at $324 million to $484 million over the next few years, according to DHS documents obtained by the Los Angeles Times.

Supporters note taxpayers won't be footing that bill – they say applicants will instead, through a $465 fee. "The program operates slowly and exclusively on the funds that are contributed by those that participate in the program, said Rep. Luis Gutierrez, D., Ill.

“You get a million of them to apply, you have $500 million,” he said.

"That’s an absolute misrepresentation,” said Sessions. “Congress has the power to control all money, whether it comes in by fee, or not."

Even with a fee-based payment, Sessions said Immigration and Customs Enforcement is already overburdened by the wave of childhood arrivals and will  be further hard pressed by the new plan to carry out basic enforcement duties.

“They've told us they're unable now to do their job. They've made clear that it’s placing America at risk. Now we're talking about another five million the president wants to be reviewed for legal status," he added. 

Sessions warned the plan will lower wages in an already job-scarce economy, while Gutierrez said applicants toil at jobs many Americans refuse to do.

“Who does he really think is going to pick those onions in 110 degrees in south Texas?” asked Gutierrez. “Seventy percent of the agricultural workers that do the picking, that do the hard labor, are undocumented, we know that. So let's not kid ourselves, the folks are already here working.”

By coming out of the shadows through the plan, many immigrants could also suddenly find themselves subject to the maze of tax laws, tax penalties, loopholes and liabilities and benefits  that U.S. citizens already face, a confounding code that could potentially drive some applicants back into the shadows.

 

Doug McKelway joined Fox News Channel (FNC) in November 2010 and serves as a Washington-based correspondent. Click here for more information on Doug McKelway