Legislatures around the country are passing state laws to get tough on illegal immigration, but legal experts say many of those laws will turn out to be unconstitutional.

More than 550 bills relating to illegal immigration were introduced in statehouses this year, and at least 77 were enacted, according to a survey presented last week at the annual meeting of the National Conference of State Legislatures.

However, NCSL analyst Ann Morse told lawmakers at the conference that a 1986 federal law forbids states from enacting stricter criminal or civil penalties for illegal immigration than those adopted by Congress.

“The federal government decided it was too complicated for the states to enact their own competing laws on this,” she said.

So what about the laws passed this year?

“I believe they’ll be tested in court,” she said.

State bills aimed at illegal immigration this year have included measures on education, employment, driver’s licenses, law enforcement, legal services and trafficking.

“Unique among the states, Georgia introduced a bill that addressed all these different policy arenas, and passed it as one bill earlier this spring,” Morse said.

Lawmakers like Tennessee state Rep. Gary Moore are frustrated that proposed federal legislation on illegal immigration has stalled in Congress.

“If we could get the federal government to give us a little more leeway, we would see a lot more reforms at the state level,” said Moore, a Democrat, who said a survey of his constituents found immigration was a top concern.

It’s unlikely the federal government will want to relinquish enforcement of immigration laws to the states, said Demetrios Papademetriou, president of the Washington-based Migration Policy Institute.

“This is a prerogative that the feds really guard, particularly in Congress, with a passion that is probably unlike anything else,” he said.

Still, the states are likely to try to acquire as much authority on the subject as they can.

“Because the Congress is unable to act, people at your level — and the local level — are beginning to take things into their own hands,” Papademetriou told lawmakers at the conference. “I think we’re seeing the beginnings of something that will gradually transfer more power to the states.”

Papademetriou was critical of enforcement-only proposals to address illegal immigration. Some other proposals, like increasing the number of U.S. Border Patrol agents by 2,000 each year for the next six years, are unlikely to succeed, he said.

“I venture to say, in my humble option, that there is no way … you can come close to that number and sustain it,” he said.

It would take tens of thousands of applicants to have enough candidates to qualify, to pass training and to become experienced border patrol agents, he said.

“And when they’re experienced enough, what’s the biggest problem with the Border Patrol? Attrition,” Papademetriou said. “Because people are not stupid: If they are well trained, they are going to find a better paying job somewhere, and an easier job.”

Arizona state Sen. Jake Flake, a Republican and a cattle rancher, agreed that attempts to seal off the border are not likely to be successful.

“I find that if you put a bunch of steers in a pasture and run out of feed, there isn’t a fence good enough to hold them,” Flake said. “And I think people are the same: When they’re hungry, there’s not going to be a fence big enough to hold them.

“I don’t think we’re ever going to change this unless we help build the economy of Mexico.”