Some Republican campaigners are calling time on Donald Trump's presidential campaign following his latest obscene comments about women.

The presidential nominee may have apologised for what he described as just "locker room banter", but Republican strategists are claiming that this is a turning point in his campaign, declaring "it's over" and the "wheels have come off".

A video clip, obtained by the Washington Post, emerged of Trump talking derogatorily about actress Arianne Zucker over 10 years ago. He was heard saying: "I've got to use some Tic Tacs, just in case I start kissing her. You know I'm automatically attracted to beautiful ... I just start kissing them.. .when you're a star they let you do it, you can do anything."

If Trump bows out of the presidential race, his running mate Mike Pence could stand as the favourite to take over from him. But Pence has also become a controversial figure in his own right over the past two decades, mainly for his views on abortion and climate change.

Pence was elected in the US House of Representatives governing Indiana's 2nd and 6th congressional districts from 2001 to 2013.

During his time as governor, he cut Planned Parenthood funding, which some say contributed to one county's HIV outbreak. He reportedly voted against nearly every piece of environmental legislation during his time as congressman including trying to stop the Environmental Protection Agency from regulating greenhouse gases. He also came under fire for signing a bill prohibiting abortions on the grounds of the race of the fetus, its gender or disability.

Just this week, he slipped up in a heated debate with Tim Kaine by saying "you whipped out that Mexican thing again". Kaine had mentioned that Trump had referred to Mexico "not sending their best" people, "they're bringing drugs, they're bringing crime, they're rapists".

It led to actress Eva Logoria challenging him over his comments.

She said: "Governor Pence - we are not a thing. We are proud American citizens. We are mothers and fathers working for a better future for our kids. And we are children studying hard and dreaming of giving back to the United States that we love. And most importantly, Governor Pence, we will be voting this November."

Pence is married to Karen Pence with whom he has three children, Michael, Charlotte and Audrey.

The 57-year-old is a supporter of the Tea Party movement, that calls for a reduction of the US national debt by reducing government spending, and for lower taxes. But it opposes government-sponsored universal healthcare. Pence refers to himself as "a Christian, a conservative, and a Republican, in that order."