Aristotle once postulated, “Nature abhors a vacuum.” Meaning that any empty space must be filled with something, even if that something is hot air. Donald Trump, with his pronouncements, promises, and pomp, is filling the vacuum created by the Republican Party.

Creating a vacuum requires two conditions. First is an active process of creating the vacuum and second is the lack of anything filling the empty space. Barack Obama created the vacuum and the GOP did nothing to fill it, or at least replace it with something of substance.

How did Obama create the vacuum? Easy. His left wing radicalism emptied the country of traditional American values and hope, leaving a vacuum of angst and despair. Two thirds of Americans believe the country is heading in the wrong direction.  Obamacare with its false promises and resulting chaos and costs. Open borders bringing the third world into our world, and making the dwindling American work force pay for it all through higher taxes. The Middle East in turmoil with radical jihadists inching closer and closer to America and Iran poised to get nuclear weapons. A thriving grievance industry based on identity group politics. And a culture of political correctness shutting down any criticism or legitimate discussion of these issues.

The IRS, the most powerful and feared regulatory agency in the country, is targeting political enemies of the Obama administration, specifically the Tea Party. No one has been held to account, no one fired, no one indicted or jailed. Meaningless Congressional hearings with lots of huffing and puffing, but no accountability. No Congressional oversight. If the political parties were reversed, this would have been a much bigger scandal than Watergate. Instead it was a lot of nothing.

Where was the GOP during these past seven years? Two landslide midterm elections gave Republicans control of the House and the Senate. They campaigned promising to stop the Obama agenda, or at least offer substantive opposition to the Democrats. Instead we hear whining and excuses of why they couldn’t fulfill any of their campaign promises.

Obamacare is still in place, funding intact. The borders are open with refugee migration programs fully funded. Abhorrent Planned Parenthood, selling aborted fetal tissues for profit remains fully funded. Far left judges are readily confirmed by a Republican controlled Senate. Budget deals are passed further increasing the national debt. In turn, debt limits are raised to accommodate the budget deals. No Republican opposition, despite being the majority party in Congress.

Where is the GOP’s bully pulpit? No effort to rally the support of the millions of voters who gave the GOP large Congressional majorities. Instead the GOP happily signs on to the Obama agenda. The agenda of the left marches merrily along, as if Nancy Pelosi and Harry Reid were still running Congress.

Along comes Donald Trump, promising to close the borders, build a wall, repeal Obamacare, stop the flood of unverifiable immigrants, with a pithy but resonating promise to “Make America Great Again.”

If Republicans were doing what they promised, offering principled opposition to the Democrat agenda, there wouldn’t be a need for a Donald Trump. Or a Ted Cruz. Instead the GOP establishment is directing far more vitriol and pushback to Trump and Cruz then they ever threw at Obama, Reid, or Pelosi. Fox News, a supposed right leaning news network, is at war with Trump. Even many good conservatives at the National Review Online are piling on The Donald.

If the Republicans functioned as an opposition party rather than an enabling party, the Obama presidency would have merely nudged the country leftward, rather than turning the country in a far left direction. Jeb Bush, Chris Christie, or John Kasich would be perfectly positioned to take over and nudge the country back to the right. The establishments of both parties would be happy as the status quo would be maintained. Only a small course correction would be needed, not the total turnaround currently necessary. Much as Bill Clinton nudging the country left after George HW Bush, followed by George W Bush nudging the country right after the Clinton presidency.

This is the void that Donald Trump is filling. Opposition to the leftist agenda of Barack Obama and his allies in Congress, the judiciary, regulatory agencies, Hollywood, academia, and the media. It didn’t have to be Trump. Actually this revolt is bigger than Trump. He just happens to be well positioned and willing to fill this void.

Which is why his supporters don’t care what he says about migrants, or John McCain, or Megyn Kelly. Or whether he was pro choice once upon a time, or invited Bill and Hillary Clinton to his wedding.

It’s about the leftist agenda driving full speed ahead, fundamentally transforming America into a country most Americans don’t recognize or want. The GOP was elected in two landslides to stop or slow the damage and the GOP did nothing. That’s the void that Donald Trump is filling. If the GOP wonders why Donald Trump and Ted Cruz are leading in the polls, all they have to do is look in the mirror.

Brian C Joondeph, MD, MPS, a Denver based retina surgeon, radio personality, and writer. Follow him on Facebook  and Twitter.