Sanders has said he's not going to run a campaign attacking Hillary Rodham Clinton, per se, but his bid for president is a long shot against the massive front-runner. So it's Politics 101: To have a chance and make a splash, Sanders has got to find a way to differentiate himself from Clinton and explain why you, dear voter, should buy into him.
And while Sanders isn't attacking Clinton directly, he's clearly running a more full-throated, traditionally liberal campaign. On basically each of the below issues, he has staked out the far left, while Clinton has offered a much murkier, more-nuanced position.
Here are the seven ways Sanders is separating himself:
1. He's much tougher on the 1 percent
Bernie Sanders is staking his entire campaign on a "political revolution" that upends the distribution of wealth in America to the top 1 percent. He has said he'll consider taxing America's wealthiest by as much as 90 percent.
"Does anybody think that that is the kind of economy this country should have? Do we think it's moral? So to my mind, if you have seen a massive transfer of wealth from the middle class to the top one-tenth of 1 percent, you know what, we've got to transfer that back if we're going to have a vibrant middle class," he told CNBC's John Harwood this week.
What Clinton has said: 2016 Democrats are zeroing in on wealth inequality. Clinton, like Sanders and Sen. Elizabeth Warren (D-Mass.), has said the system is rigged against middle- and working-class Americans.
“I think most Americans understand that the deck is stacked for those at the top. And I’m running a campaign that is very clearly stating we want to re-shuffle that deck and get back to having more opportunities for more people so that they can make more out of their own lives. And I think that is exactly what America is looking for," she told reporters in Iowa last week.
2. He's more in touch with the average voter
Sanders took a rare swipe at Clinton this week when asked about the $25 million Hillary and Bill Clinton earned in speaking fees since January 2014.
"I think that can isolate you -- that type of wealth has the potential to isolate you from the reality of the world," he told CNBC's Harwood.
What Clinton's said: Sanders gave Clinton an out when he added that being rich doesn't automatically mean you're out of touch with reality. She tried to affirm as much last week.
"Bill and I have been blessed, and we’re very grateful for the opportunities we had. But we’ve never forgotten where we came from, and we’ve never forgotten the kind of country we want to see for our granddaughter, and that means that we’re going to fight to make sure that everybody has the same chances to live up to his or her own God-given potential," she told reporters in Iowa.
3. He's more opposed to super PACs
Sanders has said he won't allow his supporters to set up a political action committee that can raise and spend unlimited amounts of money on his behalf. Not doing so would single him out among all the 2016 candidates -- Clinton included.
"I'm not going to have a super PAC in this campaign. I don't go to fundraisers where millionaires sit around the room and say here's a million, here's $5 million for your super PAC. That's not my life. That's not my world. And I think the American people are saying that is not what our politics should be about," he told the Associated Press this week.
What Clinton's said: Clinton, who is heavily relying on super PACs for her campaign, has directed her campaign-finance criticism for the future. She has said she'll support changing the country's constitution to get money out of politics.
"We need to fix our dysfunctional political system and get unaccountable money out of it once and for all -- even if it takes a constitutional amendment," she said in April.
4. He's a 'Hell no' on Obama's trade deals
Like any good liberal Democrat with union backing, Sanders is vehemently opposed to two massive trade deals President Obama is negotiating with Europe and 12 Pacific countries. Congress has recently moved to make it easier for Obama to sign those deals -- without Sanders' vote.
"The minimum wage in Vietnam is 56 cents an hour. Workers there cannot form independent unions. And if you protest government policy, you might end up in trouble. OK? What does this trade agreement have to say about that? Not a (expletive) thing," he told CNBC's Harwood.
What Clinton's said: Clinton has left the door open for a maybe-yes, maybe-no on trade.
“I’ve said over and over again, any trade deal that I would support must increase jobs, must increase wages, must give us more economic competitive power around the world.” She added: “So, I have said I want to judge the final agreement. I have been for trade agreements. I have been against trade agreements," she told reporters in Iowa.
5. In Bernie Sanders's America, college is free for everyone
Let the record show Bernie said it first. Pulling a page from Warren's agenda, he's introduced legislation to make public college and university tuition free.
"Countries like Germany, Denmark, Sweden and many more are providing free or inexpensive higher education for their young people. They understand how important it is to be investing in their youth. We should be doing the same," he said in a statement.
What Clinton's said: Nothing yet. But her campaign has hinted "debt-free college" is going to be part of its platform.
6. He was against the Iraq war first
Another policy point Sanders got to first? Opposing the Iraq war way back when it came up for a vote in Congress in 2002.
"What the issue is about — it's not just looking back in hindsight … I very much opposed the war. I worried about the destabilization it would bring to the region. Hillary Clinton and everybody else had the same information as I had, and I made my decision, she made her decision," he told CNN's Wolf Blitzer last week.
What Clinton's said: Like her campaign in 2008, Clinton's reversed course on her vote for the war when she was a New York senator.
"I've made it very clear that I made a mistake, plain and simple," she told reporters in Iowa last week.
7. Making his campaign a symbol
Sanders is trying to up the ante for his long-shot campaign by declaring it a proxy for the larger battle of wealth distribution in America.
"If I do badly, and I don't run a good campaign, and we don't get our message out, and we don't bring people together, it reflects not just on me, but on the ideas that I'm talking about," he told the AP.
What Clinton's said: In her April video announcing she's running for president, Clinton painted herself as the middle class's hero.
"Americans have fought their way back from tough economic times. But the deck is still stacked in favor of those at the top. Every day Americans need a champion. And I want to be that champion."