WASHINGTON » Conservative presidential candidates speak casually of deporting 11 million people, but what they don’t say is what it would cost, what it would take and the long odds of success.

Some researchers who have considered such a possibility envision the expansion of federal fugitive operations teams that would fan out through rural areas arresting immigrant workers picking strawberries. Poultry plants would be raided and teachers and doctors could be tasked with reporting those who seek services. The costs: as high as $300 billion.

The immigration debate continues to help drive the national conversation as Republican presidential candidates seek to prove their conservative credentials. Fighting that was reignited at Tuesday’s debate grew through the week in anticipation of this weekend’s two-day Sunshine Summit in Orlando, Fla.

At Tuesday’s Republican debate, Donald Trump reiterated his promise to send millions of immigrants back home while John Kasich, the Ohio governor, mocked the idea as “silly” and unrealistic.

“It is not an adult argument,” Kasich told Trump of the plan.

On Thursday, Sen. Ted Cruz appeared on Laura Ingraham’s radio show and accused Sen. Marco Rubio of “trying to jam this amnesty down the American people’s throats.”

Those who support stronger enforcement scoff at the Nazi-like comparisons to rounding up families. They say no one — at least no one who understands the issue — expects change overnight. But Mark Krikorian, executive director of the Center for Immigration Studies, among others, predicts the government could cut the unauthorized population significantly, maybe even by half, in less than a decade by taking some reasonable steps, such as implementing a nationwide employment-verification system. Millions would leave on their own simply if jobs were unavailable, he said.

“Some people are going to be deported, yes,” said Krikorian, whose organization seeks stronger controls on illegal and legal immigration. “There are going to be some vans. There are going to have to be some SWAT teams. There are now. But the idea that this is the way we’re going to deal with all the illegals is absurd.”

It’s impossible to predict with certainty how much it would cost to deport millions of people, let alone foretell how many civil liberty lawsuits would be filed.

One group did try.

Investigators at the conservative research center American Action Forum in March looked at the potential economic consequences.

They predict that about 20 percent of those in the United States illegally would leave voluntarily if the federal government announced it would begin enforcing mass deportation. Those would primarily be immigrants who have been here the least amount of time and have established fewer ties. That means nearly 9 million immigrantswould remain.

Doug Holtz-Eakin, who leads the American Action Forum, estimates it would cost up to $300 billion to catch, detain, process through the courts and transport those 9 million back to their home countries.

Thousands of federal agents and extra police officers would have to be hired, prisons constructed and courtrooms built, he said.

“The social destruction would be enormous. I don’t think you can get around that,” said Hotlz-Eakin, a former Congressional Budget Office director. “If you think about what’s going on on the ground, basically the police looking for everybody, checking credentials, following people. You got a police state. I can’t imagine.”

The federal government currently only has the capacity to remove 400,000 immigrants each year, according to U.S. Immigration and Customs Enforcement. That’s less than 4 percent of the population estimated to be here illegally.

There would be tradeoffs to such a dramatic expansion of current resources, said Marc Rosenblum, deputy director of the U.S. immigration policy program at the Migration Policy Institute, a Washington think tank that studies immigration patterns.

Millions of people could be found without engaging teachers and doctors, but it would take hiring tens of thousands of federal agents and empowering them to do warrantless searches and other things police currently can’t do, Rosenblum said.

Americans would be faced with serious questions about giving up many protections of individual rights.

“Are you going to focus on enforcement only in neighborhoods that have a lot of Hispanics, or are we going to randomly stop people all around the country?” Rosenblum asked. “The former is going to raise all kinds of civil liberties issues. The latter is going to be a lot more expensive.”

One thing the two views have in common is a growing consensus that Trump’s actions may be doing more harm than good for the effort to reduce the number of people here illegally.

With his remarks, other Republican candidates are less able to avoid the controversial issue seen as politically toxic for those trying to present a moderate agenda. But even Krikorian compared Trump to the guy at the end of the bar espousing opinions about immigration not steeped in reality.

“Trump means well, but he doesn’t know anything about the subject,” Krikorian said.

But Kasich’s plan, which includes a route to legal status for many of those here illegally, is “equally silly,” Krikorian said.

Krikorian’s group, the Center for Immigration Studies, described the political sparring as a “false choice” between legalizing the entire unauthorized population or physically deporting them.

The better approach, he says, is a step-by-step process that shrinks the unauthorized population. It could be done by implementing an employment-verification system that would prevent jobs from going to those who are not supposed to have them, he said. The implementation of an entry-exit system would help address those who overstay their visas. The number of people who have entered legally but overstayed their visas has been estimated to be as high as 40 percent of the 11 million people estimated to be here illegally.

Once those steps were taken and the population reduced, Krikorian said, he’d be open to what he called an amnesty for a certain number of immigrants.

“My point overall here is there is a variety of tools available to the government to shrink the illegal population over a period of a few years, and then we can see who might need amnesty or might not,” Krikorian said.

It’s not that Holtz-Eakin disagrees. He said those steps would be part of any change. But he feels promoting a simple fix, especially from the platform the presidential candidates hold, confuses the issue and fails to realize the magnitude of the situation.

“These are very appealing sound bites for some people, but when you dig into it the less appealing it looks,” Holtz-Eakin said. “It doesn’t happen as quickly as you might think. And the costs are enormous. And the conditions on the ground would be very un-American. I’m surprised at the allure that it’s both had and maintains.”