OMAHA — U.S. Sen. Ben Nelson said Sunday the current attempt to overhaul U.S. immigration policy in the Senate deals with problems surrounding immigration out of order.

Nelson said Congress should secure the border and fix the legal immigration system first, then deal with the estimated 12 million people already in the country illegally.

“If we don’t get that border secure, the number of illegal immigrants will continue to rise because the more talk there is about amnesty this week, the more likely it is that we’ll have up to a 30 percent increase in border crossings by illegals,” Nelson said.

An unlikely alliance of liberal and conservative lawmakers championed the proposal, which was announced Thursday after months of private talks among senators and the White House.

Nelson described the proposal as “amnesty with a road trip.”

The proposal orders that border improvements and a worker identification program must come first, as a trigger to other changes.

Among the key points, illegal immigrants could come forward and seek a “Z visa” and — after paying fees and a fine — ultimately get on track for permanent residency. That could take several years. Heads of households would have to return to their home countries first.

Guest workers would have to return to their home country after periods of two years. They could renew their visas twice, but would be required to leave for a year in between each time.

The deal also proposes a fundamental reordering of immigration priorities, moving the system from one based on family to one primarily designed to meet the needs of U.S. employers.

But Nelson said Sunday that the bill isn’t aggressive enough on the southern border and the United States wouldn’t be ready if word of amnesty reached the other side.

“This is not just about a number of people coming to work here because they want a better life to live here,” Nelson said. “The violence on the other side of the border is spreading to this side of the border. You’ve got not only drug dealers but you’ve got gang members coming across, that’s why we need to secure that border.”

Nelson said along with securing the border, Congress needs to fix a legal immigration process that has left many frustrated, often waiting many years to get into the country. He said that would help, among other things, reduce the number of illegal immigrants who come to the country legally but overstay their visas.

Nelson said though he would vote against the comprehensive bill in its current form, he would vote to bring it to the floor so senators could discuss it.