Take it to Hillary Clinton now and Martin O’Malley’s campaign for president might actually become a real threat.

O’Malley, who formally enters the 2016 race today, needs to draw the former secretary of state out of her protective shell and into the fray, where she’s vulnerable to a gaffe or slip-up.

The former Maryland governor has been strangely unwilling to criticize or even compare himself to Clinton, but that has to change now or he’ll just be a footnote and probably even eating Bernie Sanders’ and Lincoln Chafee’s dust.

There are a few signs of hope for O’Malley. Though Clinton has cruised so far without having to actually answer to the voters, she’s shown signs of weakness. A new Quinnipiac poll showed a stunning 53 percent of voters don’t trust her and more than half of independent voters don’t like her. That’s got to make Democrats nervous.

So O’Malley does have an opening, especially if Clinton continues to evade voters’ questions and hide behind private fundraisers and phony “roundtables.” Here’s what the Maryland Democrat needs to do to turn his chances from improbable to possible:

• Draw enough attention and buzz from voters so Clinton has to take him seriously. It worked for Howard Dean in 2004 when he caught fire and forced Massachusetts Sen. John Kerry to engage him.

• Get to know Iowans — from Davenport to Sioux City and every hog farm in between. The Iowa caucuses are the only place for O’Malley to become a serious contender. The liberal Democratic caucus-goers would be right at home in Cambridge. Without a surprising showing in the Hawkeye State, O’Malley won’t have a chance in New Hampshire and beyond.

• Be aggressive without looking like a gadfly (aka Bernie Sanders). O’Malley has been almost passive up until now, but voters — especially U.S. Sen. Elizabeth Warren worshippers — want to see a fighter.

• Demand that Clinton agree to a series of debates, especially a one-on-one showdown. The media loves debate stories and will pester Clinton until she’s shamed into doing them.

• Find a compelling personal storyline. O’Malley is a white Irish male who grew up in the suburbs, turned into a lifelong pol and became mayor of a city most voters know for police brutality and riots. You gotta come up with something better than that.

• Study George McGovern. Yes, that’s right, McGovern. The 1972 Democratic nominee was an unknown, far left, anti-war candidate who used grass roots tactics to finish close in Iowa and New Hampshire, knocking off the establishment choice, Maine Sen. Edmund Muskie.

• Put the guitar away. It’s no longer unusual or even cool for a middle-aged man to be in a rock band. And it doesn’t help to get voters to take you seriously. Case in point: Mike Huckabee.