The issue has heated up since the March slaying of Arizona rancher Robert Krentz.

The body of 58-year-old Krentz was found on his 35,000-acre (14,000 hectares) ranch, where local authorities believe he had been murdered by an illegal immigrant who fled to Mexico.

And last week Arizona law enforcement alleged that threats are coming from Mexican drug cartels to target off-duty Arizona police.

A new Arizona law has also brought the issue to a head. The legislation, which is expected to take effect soon, allows police to look into the immigration status of anyone they believe could be in the country illegally.

Civil rights advocates are slamming the law as a draconian measure that will institutionalize racial profiling, and worry that more states could follow suit. Supporters say the state had no other choice, as the federal government is taking no steps to secure the borders.

Former President George W. Bush backed an immigration reform bill in 2007 that would have provided funds to secure borders and a path to citizenship for illegal immigrants currently residing in the United States -- much like what Obama is pushing-- but the legislation failed to pass Congress.

Under the current administration, no senator has yet introduced a bill and no Republican senator has yet agreed to support one.

But there is broad public and business discontent with current immigration policy, said Darrell M. West, director of Governance Studies at the Brookings Institution, who expects a bitter battle over the issue.

James Carafano, a fellow at the Heritage Foundation, said the president's push for reform is an attempt to placate Hispanic voters in the run-up to the November Congressional elections, adding that an immigration revamp is unlikely to pass in the near term.

"The administration is pretending to address policy issues when they are really just pandering to political constituents," he said.

If amnesty were taken off the table, however, some sort of bipartisan agreement could come in 2011, he said.