The ad, which ran in Des Moines on Wednesday morning, questions Sanders' ability to "actually make a difference for you," while casting Clinton as the person "with the experience and determination to get the job done."
"The time has come to make a choice, about which candidate can actually make a difference for you," a narrator says.
While Clinton has stepped up the attacks on Sanders in the last two weeks, she has vacillated between knocking the Vermont senator, who is running close with Clinton in Iowa, and pushing her own platform and message.
"[Clinton] will build on Obamacare, not start over, break through the gridlock, not add to it, defend Planned Parenthood, not attack it, stand up to the gun lobby, not protect it, lead on foreign policy, not ignore it," the narrator adds in a not-so-subtle knock against the Vermont senator.
The ad does not mention Sanders by name, but the attacks leveled in the spot, titled "The Time Has Come," track with what the Clinton campaign has been saying about Sanders for the past month.
Clinton and her aides have accused Sanders of wanting to throw out Obamacare
to pass his single-payer health care plan and have knocked him for saying that groups like Planned Parenthood and the Human Rights Campaign, which endorsed Clinton, was part of the "establishment."
"I believe we should build on the progress we have made and go further," Clinton said on Tuesday in Iowa about health care. "But I do not want to see us either have the Republicans rip that away and turn us backward or start all over again, because there are lot of good ideas in the world but you've got to be able to act on them and make them real in people's lives."
She added, "I want action, not gridlock. I want progress, not regression."
A Clinton spokesman said this spot would fall into the same rotation the campaign is running in Iowa.
Many of her ads
, though, have focused on casting Clinton as the most prepared candidate for the presidency.
This is not the first ad comparing the top two candidates of the Democratic primary. Sanders ran an ad, titled "Two Visions," that tied Clinton to Wall Street and hit her for taking campaign donations from financial interests. The ad was surprising, given Sanders' pledge to not go negative during the campaign.
Clinton aides contend that the new ad is a policy spot, not a contrast ad and noted that, based on the New York Times
, Sanders is weighing putting a negative ad up against Clinton.
Jeff Weaver, Sanders' campaign manager, refutes the Times report, saying that their campaign is happy with the tone of their campaign and have no plans to air a negative ad.