Vermont senator Bernie Sanders took the stage last night (July 25) at the Democratic National Convention in Philadelphia to offer a full-throated endorsement of his one-time presidential-race rival, former Secretary of State Hillary Clinton.

“Any objective observer will conclude that, based on her ideas and her leadership, Hillary Clinton must become the next president of the United States,” he told the delegates and convention-goers assembled at the Wells Fargo Center, stressing the necessity of Democratic party unity to defeating Republican nominee Donald Trump.

“Our job is to do two things—to defeat Donald Trump and to elect Hillary Clinton,“ Sanders said. “It is easy to boo,” he later added, addressing the chants and heckling from some of his more ardent #BernieOrBust supporters. “But it is harder to look your kids in the face if we are living under a Trump presidency.”

Despite this clear and emphatic plea for party unity, Sanders sang a somewhat different tune at a breakfast hosted by Bloomberg Politics the following morning (July 26). According to Susan Page, Washington bureau chief for USA Today, who was in attendance, Sanders told reporters he would return to his post in the US Senate not as a Democrat, but as an independent.

Indeed, Sanders has run as independent in every previous election he’s won, and has generally not been a presence at Democratic party events. That said, he generally caucuses with Senate Democrats. He was not, however, required to officially change parties upon declaring his candidacy for president, as his home state of Vermont does not register voters with any particular party.

The website for Sanders’s presidential campaign unequivocally (and understandably) describes him as a “Democratic candidate.” But as recently as July 15, his Senate staff published a press release identifying him as “[Senator] Bernie Sanders (I-Vt.).”

Still, as evidenced by the words he delivered last night, Sanders intends to keep the party intact. “Our job now is to see that platform implemented by a Democratic Senate, a Democratic House and a Hillary Clinton presidency—and I am going to do everything I can to make that happen.” But it remains to be seen just how much he can continue to revolutionize the Democratic party when he goes back to no longer being a party to it.