The Vermont Senator harkened back to one of Clinton’s stumbles from her 2008 campaign about whether undocumented immigrants should be able to get driver’s licenses.

“When we talk about efforts to assist immigrants, Secretary Clinton prevailed upon the Governor of New York, Eliot Spitzer, who wanted to do the right thing and provide drivers licenses to those who are undocumented. She said don’t do it, and New York State still does not do it.”

“In Vermont by the way, I worked with officials, and undocumented people in Vermont do have the ability to get drivers licenses,” he continued.

When he invoked the license issue, Sanders was referencing a moment during a Democratic debate in 2007 when the moderators were unable to pin Clinton down on her views on whether or not to give undocumented immigrants drivers licenses.

After defending the reasoning behind Spitzer’s bill, Clinton said, “I did not say that it should be done, but I certainly recognize why Governor Spitzer is trying to do it.” When the moderators continued pressing her on giving a yes or no answer, she replied, “This is where everybody plays gotcha,” and still refused to answer directly.

Clinton later came out against driver’s licenses for the undocumented. But in her current campaign, she has taken has taken a firm stance this election cycle in favor of them.

During the debate, Clinton brushed off the attack and did not respond.

This article was originally published on Time.com.