TOMORROW evening in Philadelphia, Hillary Clinton will take the stage at the Democratic National Convention to accept her party’s nomination to stand for election as the president of the United States in November’s election.

It will be a truly historic moment. Clinton will be the first female presidential candidate from one of the two great parties in American politics.

And, with just over one hundred days to go, it will also mark the official start of the US election campaign. One hundred days to elect the first female president, and one hundred days to halt the horrifying political rise of Donald J Trump.

This week, following the Republican National Convention in Ohio, we’ve seen the first raft of polls which show Trump leading Clinton. The elections guru Nate Silver, who correctly predicted who would win each individual state in the 2012 election, currently gives Trump a 46 percent chance of triumphing in November’s poll.

Heads you win, tails you lose.

Trump’s ascent over the past 12 months has been unprecedented in many ways, and none of them good. He’s the first presidential candidate since Dwight D Eisenhower who is without any real political experience. He’s labelled a judge as unfair simply because of his Mexican heritage, and called on the US Military to carry out war crimes by targeting civilians in Syria if they have family connections to Daesh terrorists.

His calculated and targeted rhetoric has worked to generate newspaper headlines, TV coverage and increase his support among a clearly ever- increasing disaffected section of the American people.

At the same time, his own vice-presidential running mate previously called his policies “unconstitutional”. He’s also been labelled a threat to the national security of the USA by the Pentagon and current commander in chief.

At least Barak Obama has always understood that the threat Trump poses must be taken seriously. When the Westminster Parliament debated his proposal that, if he was elected, he would ban all Muslims from entering the United States some Tory MPs attempted to ridicule the Republican nominee, calling him a “wazzock” and a buffoon. Others agreed with me that we needed to take his threat seriously. Donald Trump shouldn’t get a free pass because he’s a billionaire with a reality TV programme.

To be fair to these Tories, they were not the only ones to underestimate Trump, or dismiss him as a peripheral figure rather than attempting to take the threat he poses seriously. But the failure by many on both sides of the Atlantic to properly evaluate the nature and scale of the danger that he presents, and to seek to face up to it effectively has no doubt contributed to leading us to the current position.

This disturbing situation is a stark lesson to us all.

No matter how strongly held our beliefs, and whether in relation to the supporters of other parliamentary parties, Brexit or the Union, those of us who believe in the democratic process need to understand the motivations of those who support our opponents. We can’t blithely dismiss the views of others; we must take them seriously if we are to overcome them. There should be no compromise with racists like Trump, but we need to build bridges with those who have chosen to lend him their support. Shouting more loudly at people who do not share your views does not work. We need to listen, understand, and adapt our own arguments if we are to win voters around, whether it’s in the rustbelt of America or over here in Scotland.

This is now Hillary Clinton’s challenge.

The future prosperity of the United States, and the safety and security of the democratic world, now rests on a Clinton victory. President Obama recognises this. Even Bernie Sanders, her fierce opponent in the Democratic primary knows it. They’ve put aside past differences to unite behind Hillary in defence of the public good.

Clinton now needs to start the process of winning back support from Trump. So I hope that when she makes her speech tomorrow evening she is tough on Trump, but also addresses the issues of alienation across their country that he has capitalised on over the past 12 months. She needs to be clear about the potential of his divisive policies, but understanding about the needs and desires of those whose views she needs to change to win.

It’s going to be a long and difficult campaign over the next one hundred days, but it’s one that must be successful. Hillary Clinton and her supporters can’t now dig in and hope to maintain their current support until November 8, they must win over voters from the other side.

The alternative is far too terrifying to imagine.