Toward the end of the last Democratic presidential debate, Joe Biden was interrupted by protesters before answering his final question of the night. While much attention has been paid to some of Biden’s answers that evening – I even ran out and bought a record player – the concerns of those demonstrators haven’t been fully examined. With the impending impeachment hearings dominating the daily news cycle, it’s unlikely the national news media will give them any attention at all.

The demonstrators were trying to bring visibility to the concerns of undocumented people in America. Their refrain was “We are DACA recipients. Our lives are at risk.” It may seem odd to many that the protesters would choose a Democratic forum to make their point. The popular narrative is that the failure of immigration reform lies squarely at the feet of Republicans. It is undisputable that in 2013, when the Gang of Eight senators pushed immigration reform through the Senate, it was House Republicans who refused to even debate the measure. Hiding behind a cowardly custom known as “the Hastert rule,” which requires the support of a “majority of the majority” to bring a bill to the floor of the House, Republican Speaker John Boehner declared the measure dead on arrival.

A more complete assessment of the immigration reform battle suggests a different narrative -- one in which Democrats have been cynically complicit in denying a solution to undocumented immigrants. The DACA activists were right to make their point during Joe Biden’s answer. No other person in that auditorium is as responsible for the precarious position of DACA kids as the former vice president.

I realize that President Trump’s rhetoric on immigration is offensive to many people, and that it seems discordant to even suggest that Democrats bear any responsibility for the current status of DACA kids. But at a time when we are examining candidate statements and video from the 1970s, the behavior of an elected official over the past decade seems particularly relevant.

The last time immigration reform had the most realistic chance of passing wasn’t 2013, it was 2007. And it was Joe Biden and Barack Obama who torpedoed it. The window for this historic deal opened in late spring of that year. It closed a month later. Forged by Sen. Edward M. Kennedy, John McCain, House Democrats, and the Bush administration, the bill would have conferred legal status on the estimated 12 million undocumented immigrants then living in America. The bill seemed headed for passage. Both top Senate leaders, Republican Mitch McConnell and Democrat Harry Reid, publicly expressed support. So did President George W. Bush.

But pro-labor Democrat Byron Dorgan of North Dakota offered a sly amendment on the Senate floor, one that would sunset the guest-worker provision after five years. This eroded just enough Republican support for the bill to upend the compromise -- as its sponsors knew it would. That was their intention. This is what is called a “poison pill” amendment: Their true aim was to undermine the carefully crafted compromise and, in the process, kill the legislation and with it the aspirations of 12 million people.

Dorgan’s measure failed the first time, but on June 6, 2007, he offered it again. This time it passed by one vote, with Barack Obama and Harry Reid -- along with four conservative Republicans -- switching their votes to support the amendment. Sen. Biden could have saved the bill, but he didn’t, voting along with Sen. Obama to effectively kill the legislation. “Who is the senator from North Dakota trying to fool?” an angry Ted Kennedy demanded of Dorgan. McCain would ask the same thing about Obama, but the damage was done. The fragile coalition supporting the legislation fell apart by summertime, meaning that 12 million newcomers to America would remain in the shadows. Reid apparently didn’t want to see George W. Bush in the Rose Garden signing the bill; likewise, Obama didn’t want McCain, the Republicans’ likely presidential nominee in 2008, claiming credit. They’d calculated that they could undermine Hispanic aspirations while simultaneously campaigning for Hispanic votes by blaming Republicans for the stalled legislation. Their cynical strategy paid off.

For Democrats who don’t want to believe that Obama and Biden helped torpedo immigration reform in 2007, just examine the record of the Democrats in 2009 and 2010. During the 111^th Congress, Democrats enjoyed overwhelming majorities in both chambers, especially the House of Representatives, where they had a huge 76-seat advantage over Republicans. With President Obama in the White House, it was a period of busy legislative activity. Democrats could have easily passed a sweeping immigration reform package in 2009 or 2010 -- or at least enacted an incremental approach such as the DREAM Act, thereby protecting those DACA kids. They didn’t.

In subsequent years, the Democrats’ alibi would be that they had no significant Republican support for immigration reform. This excuse doesn’t wash. For starters, Dodd-Frank passed with no GOP votes in the House and only four in the Senate. The Affordable Care Act was enacted without a single Republican vote. Also, Democrats would have gotten some Republican support for immigration reform, which was less toxic to Republicans than Obamacare. In fact, in 2013, when the Senate passed comprehensive immigration reform, 14 GOP senators voted for the measure (seven of whom were also in the Senate during the 111^th Congress). The House, which at that time was deeply red after the 2012 election, refused to take up the matter. When the Democrats controlled all the levers of power in Washington, they never tried to make immigration reform happen.

While Biden has tip-toed around his former boss’ status among immigration reform advocates as the “deporter in-chief,” as he did in the last debate, he has far more to answer for personally. His cynical vote for a poison pill amendment in 2007 and his lack of real leadership when he was vice president put those protesters in the room last month. Their lives are at stake because Joe Biden put politics ahead of people.