PROVIDENCE, R.I. — Democratic presidential hopeful Bernie Sanders said Sunday that his level of support for Hillary Clinton as the party’s nominee would be “totally dependent” on whether she incorporates a progressive agenda like his into her campaign against the Republican nominee.

The senator from Vermont said he would do all he can to prevent a “right-wing Republican” from becoming president, but he laid out some conditions when asked during an appearance on ABC News’s “This Week” whether he would make an “enthusiastic case” for Clinton.

“That is totally dependent on what the Clinton platform is and how she responds to the needs of millions of Americans who are sick and tired of establishment politics and establishment economics,” Sanders told host George Stephanopoulos. “If Secretary Clinton is the nominee, she is going to have to make the case to the American people, not just to my supporters, but all Americans, that she is prepared to stand up to the billionaire class, she is prepared to fight for health care for all Americans, that she is prepared to pass paid family and medical leave, make sure that college is affordable for the young people in this country.”

The appearance was one of four on the Sunday talk-show circuit for Sanders ahead of five primaries on Tuesday that could largely settle the race for the nomination in Clinton’s favor. Coming off of a decisive win last week in New York, the former secretary of state looks well-positioned, according to polls, in most of Tuesday's contests — in Pennsylvania, Maryland, Connecticut, Rhode Island and Delaware.

Sanders said he is not prepared to give up the fight, insisting again that he will take his campaign all the way through the final contests in California and the District in June. And he suggested that there are limits to what he would be able to do to bring his supporters on board with Clinton, saying, “I can’t snap my fingers and tell people what to do.”

In response to a question, Sanders also said that Clinton could strengthen her case by picking a vice presidential nominee committed to a progressive agenda.

“If she is the nominee, I would hope that she puts together the strongest progressive agenda — that says, yes, we’re going to stand with the working families of this country, we are prepared to take on the fossil fuel industry and the drug companies and Wall Street and the billionaire class,” Sanders said. “And if she has a candidate for vice president who is prepared to carry that mantle, prepared to engage in that fight, I think that would be a very good thing for her campaign.”

During the segment, Sanders was shown footage of GOP front-runner Donald Trump repeating Sanders’s recent questions about whether Clinton is “qualified” to be president. Sanders said he is not concerned that the protracted battle for the Democratic nomination could take a toll on the party’s eventual nominee.

“Not at all. I mean Donald Trump lives in his own world, he insults everybody for every reason,” Sanders said. “He’ll attack me, he’ll attack Hillary Clinton, he’ll attack his own Republican opponents. That does not concern me. What concerns me is we need to continue this debate about what is happening to ordinary people in America, and that is that the middle class continues to decline.”