As he headed off on his longest foreign trip to date, President Trump tweeted Friday that he felt he should have been running against Sen. Bernie Sanders in last year's election

Back in May 2016, then-candidate Trump did tweet that he thought the primary was rigged against Sanders.

Trump's tweets are part of his ongoing commentary about the forthcoming book from former Democratic National Committee Chairwoman Donna Brazile. In an excerpt published this week, Brazile took 2016 Democratic presidential nominee Hillary Clinton to task, claiming Clinton rigged the DNC in her favor.

More:President Trump calls Hillary Clinton 'Crooked H' in tweet after Donna Brazile story

Trump heads to Asia to talk trade, North Korea nukes