About a decade ago Fox commentator Bill O’Reilly published a book entitled Who’s looking out for you? Initially I thought it was a parody, some kind of humorous commentary on selfishness in civic life.

I was wrong. It was serious as a crutch, in some respects a cynical rebuke to Kennedy’s famous entreat to “Ask not what your country can do for you . . . ”

The truth is the Republican Party over the last decade or so has made this mantra their appeal to voters. They have become a party that tethered their Election Day successes to an appeal to the lesser angels in people, on convincing voters they need to fear forces trying to take things away from them, that they need to look out for Number One.

In short, they became the Party of Me.

Of course when your message is to “look out for me”, you have to demonize “them.” So the GOP in each election cycle made major swaths of the electorate enemies.

Not just liberals or Democrats but also immigrants, minorities, gays, believers in climate change, women who want control over their bodies, the 47 percent and supporters of sensible gun control. Especially anyone, even moderate Republicans, who failed to follow blindly their ultra-conservative dogma.

And it worked for a while, until too many “thems” created a limited pool of “me” voters from whom to draw.

So after a bruising defeat in November, the Party of Me decided it must enlarge its numbers and immediately did an about face on one of its core boogeymen.

Instead of continuing an anti-immigrant frenzy, the leaders of the Party of Me signaled an abandonment of their demagoguery and rolled out a fresh Hispanic face. Enter Marco and the water bottle.

But as much as I like Marco Rubio, all he really did in his response to the State of the Union was regurgitate the same tired old talking points that have been the anthem of the Party of Me. Government is out to get you. Obamacare is a health-care takeover.

In short, you need to look out for Numero Uno.

It was a missed opportunity for Rubio because I know he is fully capable of articulating a broader, less strident message. But worse, it is toxic to our national fabric to have a political party whose entire foundation seems to exploit people’s worst instincts.

That is why, more than ever, Democrats and right-thinking Americans must double-down on being the Party of Us.

The Party of Us believes we are in this together, not a crowd but a community, that we are at our best when we root for each other because all ships rise with the tide.

The Party of Us embraces diversity and is proud of its sense of social justice.

Fear and anger are not tools to be exploited. Hope and optimism are the tools of choice.

While we don’t tolerate fraud or waste, the Party of Us doesn’t demonize government either. Government is how we protect our freedoms, link our communities and care for our most senior and vulnerable neighbors.

Government is how our children receive the education that generates true opportunity.

In truth, the Party of Us represents the kind of country we have always aimed to be and the connections with one another that create a uniquely American brand.

Republicans, including Rubio, will have to do more to convince voters they get it. Frankly, I hope they do. America is at its best when our civic debate is about competing routes that are consistent with our national aspirations.

Dan Gelber was a state senator and former House Democratic leader from Miami.