The Bernie vs Biden show
Democratic race for the White House is gearing up, writes Ben Riley-Smith in Washington
Both are white men in their 70s. Both spent decades in Congress making their name. And now both are at the front of the Democratic pack to be the next US president.
For all their similarities, Joe Biden and Bernie Sanders have starkly different political visions. The winner could end up reshaping America.
Mr Biden's announce-ment last Thursday that he will seek the Democratic Party's 2020 nomination made him the 20th candidate in the race to take on Donald Trump.
The hopefuls have only just begun making their pitches, many introducing themselves to voters for the first time. The opening debate is not until June and first votes will only be cast next February.
Yet the opinion polls already paint a clear picture of two men way ahead of the rest: Mr Biden, Barack Obama's vice president, and Mr Sanders, the senator beaten by Hillary Clinton to the nomination in 2016.
Each represents different wings of the party and competing strategies for defeating Mr Trump, the Republican incumbent who is bullish about his prospects of re-election.
Mr Biden is a moderate. He is known for working across the aisle with Republicans, both in his 36 years as a Delaware senator and his eight as vice president.
His launch video castigated Mr Trump but was silent on policy, framing himself as the candidate with the best chance of beating the president - a factor rated highly among Democrats.
Mr Sanders is a self-proclaimed democratic socialist. The Vermont senator's progressive pitch electrified the 2016 Democrat primary race by exciting younger voters, but fell short.
In his announcement earlier this year, Mr Sanders rattled off a list of policies - free government healthcare for all, no college tuition fees, a $15 minimum wage - that would be a big step Left for the country.
That tension - between pragmatism and idealism - is one that will dominate the debate among Democrats in the coming months as they mull over the best way to win back the White House.
Reports have already surfaced about the pair's lukewarm relationship. An article in The Hill, a US political newspaper, referenced colleagues describing them as being polar opposites.
Mr Biden (76) was described as "gregarious and sociable" while Mr Sanders (77) as a policy wonk who was "wrapped up in his thoughts". They are said not to talk often, despite crossing over in Congress.
If there was doubt of the feeling that lies behind the ideological struggle, it was put to bed just hours after Mr Biden announced. Justice Democrats, a political activist group formed by Bernie staffers after his 2016 campaign, issued a series of scathing tweets about Mr Biden's candidacy.
"The old guard of the Democratic Party failed to stop Trump, and they can't be counted on to lead the fight against his divide-and-conquer politics today," the group said. It went on: "Joe Biden stands in near complete opposition to where the centre of energy is in the Democratic Party today."
Defending the comments, Waleed Shahid, the group's communications director, said a "vigorous" debate was needed and questioned Mr Biden's chances of beating Mr Trump.
"Joe Biden's campaign thinks electability is about moderation. I think electability is about motivation," he said.
Mr Trump, watching on from the sidelines with Twitter account in hand, has already given both men nicknames - a real sign he considers them rivals. To the president they are "Crazy Bernie" and "Sleepy Joe".
He has also called the race's outcome, predicting that both men will be the last two standing in a campaign that could go all the way to the Democratic presidential convention in July 2020.
But the victory of either man is not guaranteed. Both have political weaknesses that will be exploited by rivals.
Mr Sanders must show his left-wing policies will not drive away waverers and keep Mr Trump in office. Mr Biden's past moderate stances could put off progressives.
Another of the 18 candidates could yet clinch the crown. But to do so, they will have to somehow break through the Biden v Bernie Show.