For those who haven't heard of the Conservative Political Action Conference (CPAC), it's the major, annual conservative gathering in Washington DC. Organized by the American Conservative Union, CPAC is supposed to be a place for passionate debate, political renewal and in recent years, no small measure of partying. In short, for politicos, it's a pretty good time. Assuming you're attracted to the opposite sex.

On 15 February, Jimmy LaSalvia, head of GOProud, an advocacy group for gay Republicans, sent out a tweet:

@missadelgado We got kicked out last year because we are gay. Nothing has changed. We won't be at #CPAC. — JimmyLaSalvia (@JimmyLaSalvia) February 15, 2013

For gay conservatives, CPAC offers a different message: "We welcome your votes, but not your participation."

At a basic level, this political isolationism is immoral. After all, as epitomized in America's motto, e pluribus unum (out of many, one), the notion of inclusion is embedded in our nation's essence. But beyond morality, CPAC is suffering from a severe case of political delusion in banning GOProud. Joining Jackie Robinson's lesson that sporting success requires specific skills and not specific skin, gay Americans are showing why they deserve an equal part in Republican political life.

There's Ken Mehlman, a former head of the Republican National Committee who lead President Bush's successful 2004 re-election campaign. There's Mike Fleck, a Pennsylvania Republican legislator, who after announcing that he's gay, stated, "I'm still the exact same person and I'm still a Republican." Or consider Carl DeMaio, who at the end of last year, narrowly lost out on becoming the mayor of America's eight largest city, San Diego.

The key point? Effective public service does not depend on the private interactions of consenting adults. Just as excluding Cuban Americans from conservatism would have denied us Florida Senator Marco Rubio, by rejecting gay conservatives, we risk the loss of great unknowns.

Many anti-gay conservatives like to pretend that homosexual Republicans are unrepresentative, Republican in Name Only (RINO) infiltrators. Indeed, I'm often told that I must be gay because I support an inclusive movement. Yet, the reality is that homosexuality is now accepted across wide swathes of the conservative movement. This is especially true for young conservatives, the focus of CPAC 2013.

For one example, just look at the anger three years ago, when a speaker at CPAC condemned the inclusion of GOPride in that year's event. That was real anger by right wing conservative activists. It reflects the quiet but sustained advance of Republican social tolerance. Doubt me? Then have a look at the reaction to this year's GOProud's exclusion. Or visit a bar on Washington's Capitol Hill and have a conversation with some Republican staffers. Though opinions will obviously vary, the social discourse will seem a world away from CPAC's hostility.

Times are changing. But until we conservatives are willing to face up to the unmitigated absurdity of liberty alongside sexual segregation, swathes of otherwise reachable voters will continue to regard our movement as undeserving of their support. Over time, our electoral prospects will be diminished and our important arguments on issues like gun rights, the size of the state and taxation, will be delegitimized as products of a hypocritical ideology.

We conservatives must break from our reflexive understanding of equality as the watchword of a liberal-activist state. Equality isn't our enemy, it's our ally. It's the means to conservative empowerment.

America belongs to each one of us, and we all deserve the opportunity to engage and to achieve. And where we reject others simply because of the adults they choose to love, we aren't only dishonoring our fellow citizens, we are betraying the most crucial of all conservative values – individual liberty. As the greatest Republican, Abraham Lincoln, once affirmed:

"If there is anything that a man can do well, I say let him do it. Give him a chance."

Left unchallenged, CPAC's decision leads us down a sinking path. Without freedom, our conservatism is rendered a parochial meritocracy of the pure. A movement disconnected from our fellow citizens, detached from modernity and destructive of the national unity, which, in our party's birth, Republicans once so nobly defended.