Sanders kicks off second bid for president

But primary voters may want a fresh face to challenge Trump in 2020, experts say

Vermont senator Bernie Sanders on Tuesday joined a crowded field seeking the Democratic presidential nomination and pledged to fight "the powerful special interests that dominate our economic and political life".

Sanders, who lost the nomination to Hillary Clinton in 2016, enters the race with a solid core of supporters and proven fundraising ability. But at 77, Sanders himself has said he may be perceived as too old for the job, and some analysts say primary voters may want a fresh face to challenge President Donald Trump in 2020.