Donald Trump tried to pin blame for Bernie Sanders ending his 2020 presidential campaign on fellow-progressive Senator Elizabeth Warren, who did not get out of the race before Super Tuesday's delegate haul went to moderate Joe Biden, and invited the populist Vermont senator's supporters to cross party lines and support him in November.

"Thank you to Elizabeth Warren. If not for her, Bernie would have won almost every state on Super Tuesday! This ended just like the Democrats & the DNC wanted, same as the Crooked Hillary fiasco. The Bernie people should come to the Republican Party, TRADE!" the president tweeted Wednesday morning. Trade is among the issues where many on the far right and far left of American politics agree; expect Mr Trump to make an aggresive populist play for some of those Sanders supporters until Election Day.

Mr Trump for months attempted to steer the Democratic nomination, to the extent he could from outside that party, towards Mr Sanders, a self-described "democratic-socialist."

The president's play was to paint the entire party as beholden to Mr Sanders and other progressives, calling the party "extreme" and "radical" and all "socialists." He railed at his political rallies that the Democrats, if elected to the White House and given control of the Senate, would take money from average Americans and give it to illegal immigrants and low-income earners.

He also asked Ukraine's then-green president to "do us a favor though" by announcing he was investigating Joe Biden and son Hunter Biden over the younger man's business dealings in the Eastern European country while his father, as VP, was working to root out corruption within its government. That phone call led to House Democrats impeaching Trump for abusing his power and obstructing Congress, charges on which he was later cleared by the Republican-run Senate.

Mr Trump denied asking for a political quid-pro-quo, though when not using that term he and his former acting White House chief of staff, Mick Mulvaney, admitted as much a handful of times.

The move, asking a foreign leader to investigate what Mr Trump's campaign concluded at that time was his most-likely and toughest potential general election foe, was a brash move that reflects Mr Trump's take-no-prisoners style of politics.

Even as Democrats began thinking ahead to a Trump-Biden showdown, which will pit the Obama era against Mr Trump's "America first" approach, the president was back to trying to cause trouble within the not-yet-complete Democratic primary process.