Democratic presidential hopeful Sen. Bernie Sanders said in an interview broadcast Friday that he would wait to see what Hillary Clinton includes in her platform before deciding how actively to campaign for her in the fall if she is the party’s nominee.

The senator from Vermont, who has vowed to stay in the race until the Democratic convention, was asked by Andrea Mitchell on MSNBC whether he would try to persuade his young supporters to back Clinton in the same fashion that she supported President Obama after losing the nomination to him in 2008.

“Well, first of all, I’ve got to find out what her platform is, what the views are that she is going to be bringing forth, to what degree she will adopt many of the ideas that I think are extremely popular and I think very sensible,” Sanders told Mitchell.

He described the process as “a two-way street.”

Donald Trump vs. Hillary Clinton on the issues

“I want to see the Democratic Party have the courage to stand up to big-money interests in a way that they have not in the past, take on the drug companies, take on Wall Street, take on the fossil fuel industry, and I want to see them come up with ideas that really do excite working families and young people in this country,” Sanders said.

His comments came during an interview Thursday, portions of which were aired on NBC’s “Nightly News.” Other segments were broadcast Friday.

The interview underscored the challenge Clinton has ahead in uniting the party if she continues on her path to secure the Democratic nomination. Although Clinton has a formidable lead in delegates, Sanders has dominated among younger voters, and many of his supporters remained unenthusiastic about her candidacy.

Both candidates campaigned Friday in Pennsylvania, the largest of five states with primaries Tuesday.

Clinton, who has begun to pivot to the fall election and barely mentioned Sanders this week, said in Jenkintown that a contest against Donald Trump could play out like “vile” Internet bullying.

“I am hoping that if I am fortunate enough to be president and break that highest and hardest glass ceiling, it will send a message: Stand up to this,” the Democratic front-runner told a small group of women invited to discuss workplace fairness.

The Fix's Chris Cillizza breaks down what's at stake for Democrats and Republicans in the upcoming April 26 primaries. (Peter Stevenson/The Washington Post)

People make “the most vile, hateful” insults online, things they would never say to someone’s face, Clinton said. She said that coarseness is evident in politics, and particularly with Trump, the Republican front-runner.

“If I am the nominee, we could very well have a campaign that is exactly all about that: insults, derogatory comments,” she said.

She will not respond to Trump’s every insult, she added.

“You know what? It isn’t really about me. And I’m not going to respond to what he said about me,” she said. “I’m going to respond to what he has said about women in general. I’m going to respond to what he has said about immigrants. I’m going to respond to what he has said about Muslims. I’m going to respond on behalf of all the people who have been the target of his hatred and his demagoguery.”

On Friday, Sanders held a breakfast with faith leaders in Philadelphia and a forum focused on military and veterans issues in Gettysburg, where he took a shot at Trump, saying despite his tough talk he has no idea about the real “cost of war.” Sanders was also scheduled to hold an evening rally in Millersville.

While polls have shown Clinton with a double-digit lead in Pennsylvania, Sanders aides argue that he is better positioned to close the gap than he was in New York. Clinton, they say, had a unique advantage there because she represented the state for two terms as a U.S. senator.

In Pennsylvania, Sanders has sought to draw a new distinction with Clinton over their differing views on a proposal by Philadelphia Mayor Jim Kenney (D) to tax soda and juice drinks to pay for universal pre-school.

Clinton supports the idea. Sanders attacked it as an attempt “to fund child care on the backs of the poorest people in this city.”

In the segment of the interview with Sanders that aired Thursday on MSNBC, Sanders acknowledged that he has “a hard path” to the nomination following his defeat in the New York primary.

In the aftermath of Sanders’s loss in New York, his advisers have argued that even if Sanders falls somewhat short in the delegate count, he could secure the nomination at the July convention by convincing enough of the superdelegates — Democratic officials and other party insiders — that he would be the stronger candidate against Donald Trump or another Republican nominee.

As of now, Clinton leads Sanders among superdelegates who have publicly stated their preference, 502 to 38, according to an Associated Press tally. Sanders’s aides argue that the superdelegates are all still in play, however, because they do not cast a vote for the nominee until the convention.

Asked by Mitchell whether he will concede and endorse Clinton if he hasn’t secured a majority of pledged delegates before the convention, Sanders said, “Look, if we do not have a majority, it’s going to be hard for us to win.”

But, referring to his prospects with superdelegates, Sanders added: “The only fact that I think remains uncertain is if we continue to be running significantly stronger than she is against Donald Trump, or whoever the Republican nominee will be. I think that’s a factor.”

Clinton said in an interview Thursday on ABC’s “Good Morning America” that it was up to Sanders to decide when to leave the race but that she hopes he will support her in the general election, citing her support of Obama in 2008.

Clinton said that when she pulled out of the race in June of that year, some 40 percent of her supporters told pollsters they would not support Obama. That didn’t last, but it took her work and example to heal the rift, Clinton said.

“I had to get to work and I had to make the case. I nominated him at the convention. I went from group to group, even as late as the convention, convincing people who were my delegates to come together, to unify,” she said.