On Tuesday, fifteen months of official competition between Hillary Clinton and Bernie Sanders is set to end. At a morning rally in New Hampshire, the Vermont Senator is expected to formally back the presumptive Democratic nominee. The former New York Senator has made concessions to the left wing of her party, but are they enough to win over Sanders supporters? Josh Robin takes stock of their race.

Last time we saw them together, it was on a debate stage in Brooklyn, where the Vermont Senator questioned the presumptive nominee's judgment.

Bernie Sanders now may keep quiet on judgment questions. Unless it's about what he calls a greater cause:

"To make certain that Donald Trump is defeated and defeated badly," Sanders said.

The expected endorsement of Clinton comes more than a month after she effectively wrapped up the nomination.

Since then, Team Sanders no doubt grieved and hashed out a platform pushing Democrats left.

"I think we had huge success in two areas Fight for $15, and environmental issues," said Sanders supporter Nomiki Konst.

Sanders supporters Konst and Josh Fox helped write the platform.

But apart from the environment, and $15 an hour minimum wage, they say they're disappointed. At the top — the platform doesn't oppose the Trans-Pacific Partnership trade agreement known as TPP.

"The Democrats could lose this election over TPP," Fox said. "Donald Trump could camp out in Pennsylvania, Ohio, Wisconsin, Michigan — all those rust belt states  — and simply say Hillary Clinton is for pushing your jobs overseas."

Clinton says she opposes the trade deal, but President Obama backs it, making it unlikely the Democrats would strip support from the platform.

Some Sanders supporters already back Clinton. But others don't, and that may not change even after they share the stage, now as allies.

Among them are Fox and Konst, who calls Tuesday's event "half a political stunt."

"I think that Hillary Clinton — and her campaign — is trying very hard to unify through symbolism," she said. "But I'll tell you one thing and I'll make this very clear, and I'll say it to the camera, Hillary Clinton has not reached out to any of the Democratic surrogates on behalf of Bernie Sanders."

Clinton's campaign declined to comment on Tuesday's event. Officials say she and Sanders compromised over mutual goals.

Meanwhile GOP rival Donald Trump has been hoping to pick up disappointed Sanders supporters.

"A lot of those Bernie people hate Hillary Clinton - crooked Hillary," he said.

Monday, as word surfaced Democrats were trying to unify, the Republican did not mention him.