So, last night didn’t go that well for Bernie Sanders.

Despite high hopes for a strong showing in the so-called “Acela primaries,” he managed to win just one of the 5 states at play -- Rhode Island. As a result, his path to the Democratic nomination, although still open, just got a lot slimmer.

But contrary to what you might hear on the mainstream corporate media, Bernie’s win in tiny Rhode Island is actually a pretty big deal.

It wasn’t the last gasp from a candidate who’s well past his sell-by date that establishment types are making it out to be.

It was a wake-up call to Democrats everywhere about what they need to do to expand their party.

You see, there’s a reason why Bernie Sanders did so well in Rhode Island: it has an open primary, and Bernie Sanders often does really, really well in open primaries.

Including Rhode Island, most of the actual primaries he’s won this election season have been open contests or virtually open contests.

This isn’t a coincidence.

It’s the logical result of the strong support Bernie has among the independent voters who play a big role in deciding open contests, because independents can actually vote in them.

Some establishment Democrats have shrugged off Bernie’s rapport among independents as yet another example of how he’s not a “true Democrat.”

The way they see it, he’s just a johnny-come-lately who only has support among other johnny-come-latelies who could care less about the future of the Democratic Party.

This kind of thinking is so short-sighted and downright counterproductive it just boggles the mind.

Bernie’s success in open primaries and among independents isn’t a bad thing or -- it’s exactly what the Democratic Party needs.

Independents account for 42 percent of the national electorate, and while doing well among Democratic loyalists is well and good during primary season, a good general election candidate needs to be able to win at least some of the independent vote. An even better general election candidate would win the majority of the independent vote.

And here’s the thing. Bernie isn’t just winning over a key voting demographic, he’s energizing people to come out and participate in the political process as Democrats

So if the Democratic Party were smart, it’d capitalize on Bernie’s rapport with independents, as well as young people, and try to replicate it across the board.

An obvious starting point would be adopting Bernie’s positions on things like healthcare, Social Security, free college, no more stupid wars, and taking on Wall Street.

It’s these positions, more than anything else, that have drawn people to the Bernie Sanders campaign and it’s why his campaign has done so well despite all the nay-sayers in the establishment passing it off as “just another protest campaign.”

But adopting Bernie’s policies is only one part of what Democrats need to do capitalize on his campaign’s success. They also need to recreate what’s made that success possible, and that’s means making all primaries (and caucuses) open contests.

Despite what some people might think about how important is to “have Democrats elect Democrats,” closed primaries arguably hurt Democrats in the long run. They artificially limit the party’s reach and don’t give candidates any incentive whatsoever to win over anyone other than party loyalists.

Open primaries, on the other hand, do the exact opposite.

They expand the party’s reach and give candidates a real incentive to win over people who, for one reason or another, don’t feel comfortable aligning themselves with a political party.

They also make it a lot easier for voters to take part in the political process because they’re a lot easier to understand: if you’re registered to vote, you can vote, regardless of the party you belong to. It’s that simple.

In fact, a good way to synthesize open and closed primaries would be to have independent voters declare a party affiliation on election day at the polls to vote on that party's ballot, and then they're automatically registered with that party until they change their affiliation.

As the primary season winds to a close and we head towards the general election, Democrats should be optimistic.

No matter who’s the nominee, the Bernie Sanders campaign has revealed an easy way for the Democratic Party to expand its base and therefore become, well, more democratic.

It’s time for open primaries across the board.

Let’s just hope the DNC is smart enough to realize that and make it happen.