Years before the killing of Kate Steinle in San Francisco, sanctuary cities were a hot issue in the 2008 Democratic presidential primary campaign. And as it happened, the three top figures in today's Democratic party — Barack Obama, Joe Biden and Hillary Clinton — were all running for president and were all grilled, in a single debate, about their stands on the question.

Only one — Biden — said he would not allow cities to defy federal immigration law. Obama sidestepped the question but managed to leave the clear impression he would allow sanctuary cities to continue. And Clinton made clear she would leave sanctuary cities untouched.

The debate took place on September 26, 2007 at Dartmouth College in New Hampshire. Biden was questioned by Alison King of New England Cable News. She had to pull an answer out of him, but eventually got one:

KING: Would you allow these cities to ignore the federal law?

BIDEN: The reason that cities ignore the federal law is the fact that there is no funding at the federal level to provide for the kind of enforcement at the federal level you need…Part of the problem is you have to have a federal government that can enforce laws. This administration's been fundamentally derelict in not funding any of the requirements that are needed even to enforce the existing law…

KING: But yes or no.

BIDEN: I wish I'd get to talk about something I know about like foreign policy. You gotta count me in in this debate a little bit.

KING: So Senator Biden, yes or no, would you allow those cities to ignore the federal law?

BIDEN: No.

Give Biden credit; he answered the question. But Obama didn't allow himself to be cornered. Under less persistent questioning from the late Tim Russert of NBC, Obama stuck with a non-answer without giving even the slightest hint he would change the sanctuary city system:

RUSSERT: Senator Obama.

OBAMA: The federal law is not being enforced not because of failures of local communities, because the federal government has not done the job that it needs to do. And —

RUSSERT: But you would allow the sanctuary cities to exist?

OBAMA: What I would do as president is pass comprehensive immigration reform. And the federal government should be doing, which is controlling our borders but also providing a rational immigration system, which we currently don't have.

Clinton tried to avoid a direct answer, too, but ended up saying she saw no choice but to allow sanctuary cities to continue:

RUSSERT: Senator Clinton, would you allow the sanctuary cities to exist?

CLINTON: Well, in addition to the general points that have been made, that I agree with, why do they have sanctuary cities? In large measure because if local law enforcement begins to act like immigration enforcement officers, what that means is that you will have people not reporting crimes. You will have people hiding from the police. And I think that is a real direct threat to the personal safety and security of all the citizens. So this is a result of the failure of the federal government, and that's where it needs to be fixed.

RUSSERT: But you would allow the sanctuary cities to disobey the federal law.

CLINTON: Well, I don't think there is any choice. The ICE groups go in and raid individuals, but if you're a local police chief and you're trying to solve a crime that you know people from the immigrant community have information about, they may not talk to you if they think you're also going to be enforcing the immigration laws. Local law enforcement has a different job than federal immigration enforcement. The problem is the federal government has totally abdicated its responsibility.

Clinton was more direct a few months later in a 2008 interview with Fox News's Bill O'Reilly. "Are you going to crack down on the sanctuary cities?" O'Reilly asked. "No, I'm not, and I'll tell you why," Clinton answered, offering pretty much the same explanation she gave at Dartmouth.

But for a moment in 2007, the three figures who would go on to lead the Democratic party for years to come all had to answer the sanctuary cities question. And of course, under President Obama, cities across the country have been allowed to ignore the law, leading, years later, to the death of Kate Steinle on the pier in San Francisco.