Sanders expected to endorse Clinton on Tuesday

Bernie Sanders will join one-time rival Hillary Clinton for a presidential campaign rally in New Hampshire on Tuesday, heightening expectations he will deliver his long-awaited endorsement of the presumptive Democratic nominee.

Bernie Sanders gives his "Where We Go From Here" Speech. Source: AAP

With Sanders appearing to coalesce around the former secretary of state's bid to become the nation's first female leader, her Republican opponent Donald Trump heads to Indiana, raising speculation he could pick the state's governor, Mike Pence, as his running mate.

The campaigns of Sanders and Clinton both said Monday that Sanders will join Clinton at a high school in the city of Portsmouth "to discuss their commitment to building an America that is stronger together and an economy that works for everyone, not just those at the top."

Sanders has yet to endorse his former rival for the Democratic nomination, but he has taken incremental steps over the past month toward embracing her campaign.

The New York Times reported last week that Sanders's anticipated pledge of support is the result of weeks of talks between the two campaigns aimed at unifying the party.

Clinton clinched enough delegates to secure the nomination in early June, after a yearlong battle with Sanders, a US senator from Vermont.

But the feisty self-described democratic socialist nevertheless has refused to concede defeat to his more moderate rival, although he has said he will vote for Clinton and will do anything to help defeat Trump.

Sanders has been negotiating with the Clinton campaign to ensure that his ideas are part of the party platform presented at the Democratic National Convention later this month, when Clinton is formally nominated.

Party officials met over the weekend in Orlando, Florida to finalize the Democratic platform, and they described it as the most ambitious and progressive platform in history.

The party reached agreement on language concerning climate change, health care and raising the minimum wage in America to $15 per hour. But they reportedly failed to reach common ground on the Trans-Pacific Partnership trade accord.

"Democrats reaffirmed our commitment to addressing the needs of everyday Americans, refusing to allow right wing extremists to unravel the progress we have experienced over the past eight years under President (Barack) Obama," Democratic convention chief executive Leah Daughtry said Sunday in a statement.

Pence for VP?

Trump meanwhile was campaigning Monday in Virginia with potential vice presidential pick Chris Christie, the governor of New Jersey and a former Republican presidential hopeful, amid reports that the billionaire real estate tycoon will choose a running mate in the coming days.

Christie has been a loyal Trump surrogate since shortly after bowing out of the race, and his experience running a populous state could be seen as critical for a candidate who has acknowledged his own lack of political and government expertise.

Pence would bring executive experience as well, along with a perceived steady hand at the tiller that could help counter the narrative that Trump is too incendiary and quick to provoke.

Former Trump advisor Michael Caputo expressed confidence late Sunday that Trump will announce Pence as his pick during campaigning in Indiana.

"I put all my chips on Pence/VP announcement at this event," Caputo tweeted. "Right guy. Right timing. Right place. #TrumpPence2016."

Pence, who made a tepid endorsement of Senator Ted Cruz but switched to Trump when Cruz dropped out, told reporters Tuesday he believes Americans need strong and "clear-minded leadership."

"And I'm prepared to make that case anywhere across Indiana and anywhere across this country that Donald Trump would want me to."

Clinton too is shrinking her VP pool, with Senator Elizabeth Warren, Senator Tim Kaine - with whom she campaigns Thursday in Virginia - Obama cabinet secretaries Tom Perez and Julian Castro, and congressman Xavier Becerra believed to be on her short list.