With Hillary Clinton locked in a general election with the bombastic, unpredictable, and oft-incendiary Donald Trump, former Democratic presidential candidate Bernie Sanders has some ideas. On MSNBC's Morning Joe on Sept. 16, Sanders had some advice for Clinton, and it amounts to this: Start running on issues, rather than "all of this personality stuff." While he was speaking more generally, this could apply to Clinton's performance in the upcoming first presidential debate.

Specifically, Sanders said that he thinks Clinton should be focusing on many of the issues he pressed her on throughout the campaign ― things like health care, tax and income equality policy, climate change, and one of his signature issues, eliminating student debt and ensuring higher education for all. Sanders explained further:

In politics, too much we look at personality, we like you, we don't like you. And I think we gotta back away from that and say 'we're not looking at Trump or Clinton, we're looking at the needs of the American people.' And if you just go down the list, in terms of experience, but also in terms of views on the ― I worked with Clinton, Joe, at the end of the campaign, on higher education. And what we concluded, and she is public on this, and we'll make this happen, is that every family in America of $125,000 or less, that's 83 percent of people, will be able to send their kids to a public college or university tuition free. That's pretty good, Joe, that's pretty damn good.

This is a slightly strange tactic for Sanders to propose to Clinton, considering she's notoriously more comfortable with policy than personality. She really hasn't tried to run on the strength of her persona or life story — at least, not nearly to the extent that, say, President Obama did in 2008. But in a certain way, it makes sense that Sanders would say this. Although the two are often far apart in terms of the relative orientations of their proposals, both are first and foremost geared toward thinking in terms of policy. And with a daunting, harshly negative general election campaign heavy on character attacks, it's clear that Sanders worries Clinton's actual proposals and affirmative case for herself are getting lost in the weeds.

Sanders repeated that he hoped that millennials would "look at the issues," also citing Clinton's desire to increase taxes on the rich, as compared to Trump's harshly regressive tax cut, which would free up more income for millionaires and billionaires like himself:

So I would just simply say to the millennials, to anybody else, just look at the issues. Don't get hung up on Trump's kids and whatever, the story of the birther issue. Stay focused on the issues of relevance to your life, I think Clinton is far and away the superior candidate.

Somewhat counterintuitively, however, Sanders also stressed that he believes many voters, including those who were once his supporters, are motivated by the "bigotry" argument. Despite the fact that he also suggested voters shouldn't get "hung up" on the birther issue, Trump's years-long spreading of conspiracy theories about President Obama's birthplace has helped make mainstream a movement that has always, at its core, been an exercise in racism. Perhaps Sanders' point, though, is that highlighting offenses against Obama may not move as many undecided votes as an emphasis on the suffering of the economically disenfranchised. He explained:

I'll tell you, there is an issue that is bringing the people who voted for me, I think, together. That is this issue of bigotry. You can disagree with Clinton on this or Trump on that, but we have come so far in this country in struggling against discrimination and racism and sexism.

Darren McCollester/Getty Images News/Getty Images

Sanders also cautioned his former supporters, and young voters in general, to think long and hard before casting a "protest vote," saying that when all is said and done, either Clinton or Trump will be elected president, and the consequence of third-party defections could be disastrous:

Think hard about it. This is not a governor's race, or a state legislative race, this is the presidency of the United States. And I would say to those people out there thinking about a protest vote, think about what the country looks like, and whether you're comfortable with four years of a Trump presidency. I would suggest to those people, let us elect Hillary Clinton as president, and the day after, let us mobilize millions of people around the progressive agenda, which by the way was passed, as you know, in the Democratic platform.

Sanders is reportedly planning to hit the campaign trail for Clinton in the days to come, and that can only be a help to her. He's previously promised to do "everything in [his] power" to prevent a Trump presidency.