Bernie Sanders, the runner-up for the Democratic presidential nomination, plans to return to the campaign trail after Labor Day, with an eye toward energizing working-class and young voters to support his former rival, Hillary Clinton, he said Friday.

“I look forward to it,” the senator from Vermont said in an interview. “I feel very strongly that Donald Trump would be a disaster for the country. I want to do everything I can to see that Secretary Clinton wins.”

Sanders, who endorsed Clinton last month, ticked off a list of states that he is likely to hit in coming weeks, including some where he won primaries and caucuses (New Hampshire, Maine, Michigan and Wisconsin) and some where he fell short but ran strongly among key segments of the electorate (Ohio, Pennsylvania and Nevada).

Sanders said that during some of those visits he will also campaign on behalf of Democratic Senate candidates, including Katie McGinty in Pennsylvania, Ted Strickland in Ohio and Maggie Hassan in New Hampshire. He also is planning to campaign for other progressive down-ballot candidates, he said.

Sanders said he plans to hold large-scale rallies, which were a staple of his campaign, drawing from both his and Clinton’s lists of supporters.

“I think we can create large turnouts,” he said.

Sanders has kept a low public profile since the Democratic convention, where he offered his full-throated support of Clinton during a prime-time speech, but some of his delegates continued to protest the outcome of the primaries.

He has been working on a forthcoming book on his experience running for office and vision for the country’s future.