Donald Trump Advises Bernie Sanders to Run as an Independent Donald Trump suggests Vermont senator "show them" and go back to his roots.

 -- As voters in five different states head to the primary polls today, there is another unlikely alliance, of sorts, forming.

Donald Trump, the Republican front-runner who has expressed empathy for Bernie Sanders, is offering him some unsolicited advice.

"Bernie Sanders has been treated terribly by the Democrats — both with delegates & otherwise," Trump tweeted this afternoon. "He should show them, and run as an Independent!"

Sanders has run as an independent for most of his political career and is the longest-serving independent in congressional history. But he joined the Democratic Party to run for president and his campaign manager told Bloomberg News that Sanders would be a Democrat for life.

Though Sanders and Trump's views are vastly different, these two populist stars do have a few similarities. For one, they have enjoyed some of the largest crowd sizes of any presidential candidate. And Trump has likened their candidacies, comparing the struggle he says both men face.

"This is a crooked system,” Trump said earlier this month in Rochester, New York. “I’m not a fan of Bernie. I couldn’t care less. As far as I’m concerned, I couldn’t care less about Bernie. But he wins. And he wins. Like me.”

Trump has decried the primary system in both parties, calling them rigged, accusing the votes of being in the hands of the delegates not the people.