Giuliani went to court to preserve the policy, suing over a 1996 attempt by Congress to undo the city's protections. He lost, but Mayor Mike Bloomberg later issued a new, broader version of the policy that is still in effect.

In the presidential campaign, Giuliani and Romney are talking tough on immigration, even opposing the bipartisan immigration overhaul backed by President Bush. Yet their records are not necessarily tough. For example:

--Several illegal immigrants worked on Romney's lawn as employees of a lawn care company; Romney said he didn't know the company had hired illegal workers.

--As mayor, Giuliani often spoke positively about illegal immigrants: "If you come here, and you work hard, and you happen to be in an undocumented status, you're one of the people who we want in this city," he told The New York Times in 1994.

--Both Romney and Giuliani spoke favorably of 2006 legislation providing a path to citizenship for illegal immigrants; they opposed a similar bill earlier this year.

Immigration inflames conservatives in early voting states such as Iowa and South Carolina, where some argue that illegal immigrants are straining schools and hospitals, lowering wages or taking jobs from law-abiding citizens.