Washington: The White House race shifted into top gear on Monday for the final stretch, with Donald Trump airing his first campaign ad and Hillary Clinton deploying her husband, former president Bill Clinton.
Trump doubled down on every inflammatory campaign assertion in the ad such as temporarily shutting down Muslims and building a wall along the southern border to stop immigration. And, the voice-over in the 30-second ad says the Republican frontrunner will "quickly cut the head of ISIS (another name for the Islamic State) and take their oil".
The ad began airing on Monday to widespread media attention, as it has been with everything Trump. The Washington Post carried an "exclusive" first look at it, with a behind-the-scene account.
Trump has several other ads lined up as, he says, he finally begins to spend money. His campaign, he has said, has been severely under-budget and he feels guilty about not spending.
Other candidates are also stepping up their game as the race enters the final stretch before the Iowa caucus on February 1, the first stage in the nominee-selection process for both parties.
On the Democratic side, former president Bill Clinton hits the campaign trail later on Monday in a development that experts say can both boost and mar his wife's second run.
Clinton is popular with Democrats, specially African -Americans has been called the first black president and was used by President Barack Obama in 2012. But he also brings to the race controversies about his sex life. References to Monica Lewinsky, the White House intern with whom he had a relationship as president, have already started.
Trump has called him "degenerate", to counter charges of being "sexist" levelled against him by Hillary, and other candidates have said the former president is fair game.
Bill Clinton can also go off the message, as he did when his wife first ran for the White House in 2007-8, and frequently became the focus of her campaign through stray remarks.
But President Clinton, who has also been called the explainer-in-chief in a nod to his ability to dumb down the most complex of policy issues, can be a tremendous asset on the campaign trail.
He is scheduled to do several solo events in New Hampshire state, which is second in the nominee-selection process but does it through state-wide polling unlike Iowa's caucuses, meetings.