WASHINGTON - Vermont Senator Bernie Sanders launched his second campaign for president on Tuesday with an all-out assault against Donald Trump, entering an already crowded field in the hope of improving on his second-place finish to Hillary Clinton in 2016.

'You know as well as I do that we are living in a pivotal and dangerous moment in American history,' the 77-year-old said in a more than 10-minute-long launch video.

'We are running against a president who is a pathological liar, a fraud, a racist, a sexist, a xenophobe, and someone who is undermining American democracy as he leads us in an authoritarian direction.'

Sanders called for 1 million Americans to help him turn Trump into a one-term president.

'We're gonna win,' he said on the 'CBS This Morning' program. 'We are going to also launch what I think is unprecedented in modern American history and that is a grassroots movement.'

President Trump's 2020 national press secretary, Kayleigh McEnany, fired back.

'Bernie Sanders has already won the debate in the Democrat primary, because every candidate is embracing his brand of socialism,' Mcenany said in a statement.

'But the American people will reject an agenda of sky-high tax rates, government-run health care and coddling dictators like those in Venezuela. Only President Trump will keep America free, prosperous and safe.'

Republican National Committee spokesman Michael Ahrens sniffed in a statement that Sanders 'is a self-avowed socialist who wants to double your taxes so the government can take over your health care.'

'The vast majority of voters oppose his radical agenda, just like they are going to oppose all the 2020 Democrats who have rushed to embrace it.'

In a 1,500-word email to supporters, Sanders said his democratic socialist ideals, including socialized medicine and upper-income tax hikes, were considered '"radical" and "extreme"' in the last election cycle but are gaining broader acceptance.

'Three years have come and gone. And, as result of millions of Americans standing up and fighting back, all of these policies are now supported by a majority of Americans.'

'Together, you and I and our 2016 campaign began the political revolution. Now, it is time to complete that revolution and implement the vision that we fought for.'(FA)