Washington: Just a few months ago it seemed unlikely verging on implausible, yet here we are: Bernie Sanders is on track to win the Democratic Party's presidential nomination.

It's well past time for people to take the 78-year old democratic socialist seriously - not just as Donald Trump's most likely opponent in November but as a potential president of the United States.

"We're going to win this election," said Bernie Sanders, in San Antonio, Texas, after the Nevada caucus. Credit:AP

Could a man so left wing and so old really be a serious contender for the presidency - especially given he had a heart attack in October? Yes he could, and he is.

To his benefit, Sanders has been chronically underestimated throughout his long political career and that continues to this day.