By David S. Levin, writer from New York

It’s hardly a secret that many Republicans across the United States hold Donald Trump directly responsible for the creeping demise of their once grand political party. The party of Lincoln, Reagan and Teddy Roosevelt. A proud party with a long, conservative lineage and history.

But three years into his presidency, Donald Trump has left the Republicans politically disfigured and fatigued by his reckless antics. He’s like a bad punchline that few people understand. And despite his successes (yes, he’s had some), many of his policies continue to antagonise friend and foe alike, moving the party even further outside the new political mainstream.

For many on both sides, his presidency is nothing short of a national emergency right up there with climate change and the threat of nuclear war. But despite all the angst, Trump isn’t actually the reason behind the Republicans downfall. He’s more of a symptom of it.

What’s killing off the Republicans is really much simpler. It’s the maths. It’s the changing generational and ethnic demographics in the United States as the electorate gets younger, browner and more Asian; most of whom historically vote Democratic at the ballot box.

Just look at the numbers. There are currently 73 million multi-ethnic millennials and 68 million ideologically similar gen-zers in the U.S., who together, comprise the largest voting bloc in the country. Not surprisingly, a Gallup poll recently found that seven in ten millennials would vote for a socialist candidate for president. Their bet is that a new, socialist-inspired Democratic party led by the likes of Bernie Sanders or Elizabeth Warren could seize the levers of power in Washington and sand blast away all the sins of the past. Good luck with that.

To many of these younger Americans, the U.S. and by extension, capitalism, is a rigged system of biased government institutions, fossilised politicians, irresponsible corporations and billionaire business leaders who have razed the country for personal gain and cheated them out of the quality of life they deserve. And they gripe that because of this, their lives are eternally stuck in the mud – wheels furiously spinning, dirt flying everywhere, and going nowhere fast.

To them, it’s time for a change and they have the wind at their back. The natural order of the universe has it that every generation passes the torch on to the next one. And they are ready. According to the Pew Research Center, it is projected that the millennials will overtake the baby boomers as America’s largest generation by 2020 as the boomers continue to age and decline as a percentage of the population.  

When voters go to the polls in November, baby boomers and those remaining from the generation before them, will account for four in ten eligible voters. This is a significant drop from the year 2000 when the number was seven in ten voters. And with each passing election cycle, those figures will continue to trend downward. In addition, the balance of Americas ethnic make-up is changing as well. The days of a white, Euro-centric dominated U.S. population – who comprise the base of the Republican party – are dwindling. None of this bodes well for the Republicans.

What all this means for U.S. politics in the years to come is nothing short of a sea change. A grass roots reorganisation of the power structure in the country. A reshuffling of the political deck, jokers and all.

The Democrats, once predominantly a party of moderates and centrists, will continue to gradually be overrun by younger, quasi-progressives pushing the party further left. And their ranks will steadily be fed by immigration and naturalisation as time goes on. Within ten to 15 years, they will be ideologically unrecognisable to many people in the country today. But one thing is certain. As they continue to broaden their appeal to younger Americans and a diversifying ethnic base, they will be a force to be reckoned with.

The Republicans on the other hand, are at a crossroads. They have the opposite problem. And it’s a simple one. Adapt or die. They remain frozen in time and largely outdated as they try to hang onto values and ideas that much of the country is outgrowing.

And while there are a number of scenarios that would have Donald Trump winning reelection in 2020, the problem for the Republicans is longer term. Within two, maybe three, election cycles it is unlikely they will be able to turn out enough votes to win the White House again, or for that matter, the Congress.

As they say in chess, checkmate.

To even remain in the conversation in the years ahead, they would need to radically redefine their brand and move from the conservative right to a more diverse and inclusive center. A gargantuan task for sure, a sociopolitical tug of war, and one that would be met by blunt force from many of the party leaders.

But it may already be too late for them anyway.

Because as the shifting demographics of age and ethnicity continue to intersect, combined, these numbers will ultimately tilt the balance of power leftward toward the Democrats. And as the country further diversifies in the years ahead largely due to immigration, this perfect storm of youth and colour will be impossible for the Republicans to deny. Or beat in an election.  

Unless they dramatically recalibrate their message to address these new demographics, fewer and fewer voters will find anything in common with their platform and they will be left on the outside looking in for years to come.

Or who knows. Maybe even longer.