[WASHINGTON] Bernie Sanders will join one-time rival Hillary Clinton for a campaign rally Tuesday in New Hampshire as the presumptive Democratic nominee faces Donald Trump, who has proclaimed himself "the law and order candidate" amid rising gun violence.
With Mr Sanders expected to endorse the former secretary of state's bid to become the nation's first female leader, Mrs Clinton's Republican opponent Donald Trump will campaign in Indiana.
His scheduled appearance with governor Mike Pence is raising speculation that Mr Trump could pick the state's chief executive as his running mate.
The campaigns of Mr Sanders and Mrs Clinton both said Monday that the two will join together 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."
Mr 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 Mr Sanders's anticipated pledge of support is the result of weeks of talks between the two campaigns aimed at unifying the party.
Mrs Clinton clinched enough delegates to secure the nomination in early June, after a year-long battle with Mr 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 Mrs Clinton and will do anything to help defeat Mr Trump.
Mr 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 Mrs Clinton is formally nominated.
Party officials met over the weekend in Orlando, Florida to finalise the Democratic platform, which they described as the most ambitious and progressive yet in history.
The party reached agreement on language concerning climate change, health care and raising the minimum wage in America to US$15 per hour. But they reportedly failed to reach common ground on the Trans-Pacific Partnership trade accord.
Mr Trump meanwhile was campaigning Monday with New Jersey governor Chris Christie in Virginia, where Mr Trump proclaimed himself the only candidate who will be able to keep Americans safe.
"I am the law and order candidate," the presumptive Republican nominee said in Virginia Beach.
The declaration, reminiscent of remarks made by former president Richard Nixon in his 1968 campaign, came as Mr Trump highlighted recent killings including the horrific shooting deaths of five Dallas officers in a gunman's sniper-like assault.
"The attack on our Dallas police is an attack on our country. Our whole nation is in mourning," Mr Trump said, as he pledged to "fight" for law enforcement personnel and ensure they have Washington's full backing. "Without safety we have nothing."
Mr Trump and Mrs Clinton both halted their campaigning for a day after Thursday's Dallas police murders.
But on Monday Mr Trump ripped into Mrs Clinton as "weak, ineffective" and hobbled by the criticism about her use of private email during her tenure as top diplomat.
"Crooked Hillary is the secretary of the status quo, and wherever Hillary Clinton goes, corruption and scandal follow," Mr Trump said.
Mr Christie, a potential vice presidential pick, joined Mr Trump as reports swirled that the billionaire real estate tycoon will choose a running mate in the coming days.
Mr Christie's experience running a populous state could be seen as critical for a candidate who has acknowledged his own lack of political and government expertise.
Indiana's Mr Pence would bring executive experience as well, along with a perceived steady hand at the tiller that could help counter the narrative that Mr Trump is too incendiary and quick to provoke.
Former Trump advisor Michael Caputo expressed confidence late Sunday that Mr Trump will announce Mr Pence as his pick during campaigning in Indiana.
"I put all my chips on Pence/VP announcement at this event," Mr Caputo tweeted.
"Right guy. Right timing. Right place. #TrumpPence2016."
Mr Pence, who made a tepid endorsement of Senator Ted Cruz but switched to Mr Trump when Mr Cruz dropped out, told reporters Tuesday he believes Americans need strong and "clear-minded leadership."
"I'm prepared to make that case anywhere across Indiana and anywhere across this country that Donald Trump would want me to," he said.