Rep. Ed Markey (D-Mass.) delivered a stump speech this week in his campaign for Secretary of State John Kerry's Senate seat, suggesting that the overturning of the Supreme Court's pro-slavery Dred Scott decision could be a precedent for repealing the more recent Citizens United ruling, which gave way to the creation of super PACs.

"The Constitution must be amended," Markey told attendees at the event. "The Dred Scott decision had to be repealed, we have to repeal Citizens United."

(Watch Markey's remarks in the video above)

In 1857, the Supreme Court ruled against Scott, a slave who had sued for his family's freedom, in Dred Scott v. Sandford. The ruling provided legal backing for slavery and found that people of African descent were not considered U.S. citizens and therefore not granted the protections of the Constitution. The decision became widely regarded as the worst ever made by the court and was eventually overruled by the Fourteenth Amendment in 1868.

The Supreme Court's 2010 Citizens United decision opened the door for super PACs, which can now channel unlimited contributions from individuals, corporations and unions into elections.

The National Republican Senate Committee quickly pounced on Markey's comments, accusing the Democrat of comparing federal campaign finance law to the "horror of slavery." The NRSC also attacked Markey's comments as hypocritical because he's accepted millions in PAC contributions throughout this congressional career.

Markey has remained a staunch opponent of the sort of unfettered influence encouraged by Citizens United and super PACs, however. Last month, he called for a "people's pledge" to keep spending by independent groups out of the election. And in a response to the recent Dred Scott comparison, Markey restated his disapproval of current campaign finance laws.

"The Citizens United ruling is poisoning the democratic process in America, and that is completely wrong. Karl Rove, the Koch Brothers and anonymous special interests have no place in our elections and no place in this Senate race. I repeat my challenge to all Republican candidates to accept the people's pledge to keep this toxic outside spending and negative advertising out of the Massachusetts Senate race," Markey said in an email to The Hill.

UPDATE: 2:25 p.m. -- Rep. Stephen Lynch (R-Mass.), who is also running for Kerry's Senate seat, responded to Markey's comment, stating his opposition both to the comparison and Citizens United more generally.

“I don’t think it’s right to compare Citizens United to the Dred Scott decision. Dred Scott kept an entire race of people in bondage and perpetuated the horror of slavery in America. I’m not sure there are any Supreme Court decisions that rival Dred Scott in infamy," Lynch said. "I will say that Citizens United is certainly one of the worst Supreme Court decisions of my lifetime, and I would support a Constitutional amendment to overturn that decision. Granting citizenship to corporations, which are state-created entities that are immortal, greatly diminishes the rights of ordinary citizens.”

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