ABC News April 7, 2016

War of Words: Sanders and Clinton Spar Over Qualifications

WATCH: Hillary Clinton Questions Bernie Sanders as a Democrat

The decorum between the Democratic presidential candidates appears to be on shaky ground as the two spar over each other’s credentials.

The latest battle reached its pinnacle as Senator Bernie Sanders listed a host of reasons why he thinks former Secretary of State Hillary Clinton isn't qualified to be president.

Rather than focusing on the positions she has held in public service, Sanders has been ticking off a list of policy positions he disagrees with, including her vote for the Iraq War and various trade agreements.

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Comments that Clinton made began the back-and-forth, but she is now trying to take the proverbial high road when asked about the criticisms. The former Secretary of State said she found Sanders’ jab to be "kind of a silly thing to say" and went on to reiterate she would support him over others.

"Look, I don't know why he’s saying that,” Clinton said while riding on a subway in the Bronx this morning. “But I will take Bernie Sanders over Donald Trump or Ted Cruz any time. So let's keep our eye on what's really at stake in this election."

The battle between the two Democratic candidates comes as they set their sights on New York, the next state to hold a primary.

In addition to comparing policy, the two are also vying for street cred as they try to win over supporters in a state where they both have ties. Clinton moved to New York after leaving the White House and served as the state's junior Senator for eight years, while Sanders was born and raised in Brooklyn before spending his adult life and holding office in Vermont. Sanders’ campaign manager Jeff Weaver confirmed to ABC News that they, “expect to spend a substantial amount on advertising in New York.”

Hillary Clinton rides the New York City subway, April 7, 2016.

The latest New York-specific polling by Quinnipiac University, released on March 31, showed Clinton leading by 12 points in the state.

The saga started when Clinton criticized remarks Sanders made during an interview with the editorial board of the New York Daily News. The Vermont Senator seemed to stumble with answers about how exactly he would break up the country’s largest banks or pass some of his other policy agenda items.

“I think he hadn't done his homework and he'd been talking for more than a year about doing things that he obviously hadn't really studied or understood,” Clinton said during an appearance on MSNBC's "Morning Joe" on Wednesday. “That does raise a lot of questions.”

Later that night, Sanders responded at a rally in Philadelphia, claiming that Clinton "quote unquote" said he was not qualified to be president.

"Secretary Clinton appears to be getting a little bit nervous," Sanders told the crowd of thousands at Temple University.

Mark Kauzlarich/Reuters
Democratic U.S. presidential candidate Bernie Sanders speaks at a press conference with union members in Philadelphia, April 7, 2016.

"She has been saying lately that she thinks that I am quote unquote, not qualified to be president,” he said. “Now, let me, let me just say in response to Secretary Clinton: I don’t believe that she is qualified if she is, through her super PAC, taking tens of millions of dollars in special-interest donations."

Clinton's spokesman Brian Fallon responded on Twitter hours before Clinton herself would respond.

MaryAlice Parks contributed to this report.