Mayor Antonio Villaraigosa hasn't had a lot to say about immigration lately. It wasn't high on his agenda until 500,000 or more people marched through downtown. He did a media op for cameras that day and has addressed some of the protests since, and for that Villaraigosa says his letters have been running 500 to 1 against. In a sit-down with the Times' Jim Newton, he says he supports the McCain-Kennedy reforms in Congress. Excerpts of the Q-and-A that ran Saturday:

Q: Overall, is immigration a positive or negative issue for you?

A: Over the years, as both a legislator and now as mayor, I've focused on education, healthcare, jobs, because those are the issues that touch the lives of most of my constituents. But when 500,000 people march in peace on an issue that's so important to their lives, their livelihood and their families, I feel compelled to get involved, regardless of whether it's a good issue or a bad issue for me.

Q: Illegal immigrants place some burden on city services, whether it's fire or police or sewer or whatever. Is there any way to measure the cost that the city of Los Angeles pays to care for people who are here illegally, and is that a cost worth paying?

A: I don't know what the cost of providing services to the undocumented would be, but I do know this: The responsibility for those costs is the federal government's, and for more than a decade I have maintained that the federal government, which receives the Social Security and income taxes generated by these immigrants, should reimburse cities and counties for any expense incurred.

Q: What makes [McKain-Kennedy] it superior to other bills?

A: It rejects the idea that we would take 12 million immigrants and turn them into felons. It includes tougher enforcement, employer sanctions for businesses that hire the undocumented. Smart border security. Collaboration with our neighbors. And it gives the 12 million undocumented immigrants a pathway to legal status, provided they pay a fine, pass a background check and learn to speak English. This is important. Finally, it doesn't pull these people ahead of the line.

Q: Would legislation that legalizes some immigrants, based on how long they have been in this country, and leaves some others illegal help or hurt this situation?

A: I think it's impractical, and it would be a bureaucratic nightmare.