The implosion is so big it’s drowning out the “he said this monstrous thing” or “that easily caught lie.” Donald Trump has moved from the chaos candidate to the kamikaze candidate to the crazy-as-a-loon candidate.

But none of his behavior is new. He’s been incoherent and ignorant — vulgar and indecent — since he started his campaign. The list of Republican defectors is now growing, but what took it so long?

In truth, the groundwork for Trump’s sort of candidacy was being laid decades ago. Here are five signposts:

1) The rise of right-wing talk media. The business model that serves Rush Limbaugh, Bill O’Reilly and Laura Ingraham seemed to serve the Republican Party at first. It riled up listeners with grievance, self-pity and the belief that Democrats are not people they just disagree with but evil. A fevered public became conditioned to regard normal politics as a war for America’s soul.

2) The Bill Clinton impeachment. In 1998, Republicans doggedly pursued the president over a sexual indiscretion, sending U.S. governance into the deep freeze for months. So grotesque was the overkill that public sympathy swung to Clinton. (He left office with a higher approval rating than did Ronald Reagan.) Most Republicans ignored the lesson there.

3) In-your-face obstructionism. Shortly after Barack Obama’s election, Senate Republican leader Mitch McConnell infamously announced: “The single most important thing we want to achieve is for President Obama to be a one-term president.”

Putting politics above governing — and at a time of great economic hardship — created an opening for a Trump-like candidate. It hurt government’s ability to deal with the sort of problems that have Trump supporters fuming. For example, the Republican House leadership blocked a comprehensive immigration reform bill that would have tightened the borders. That left the problem to fester year after year.

4) The debt ceiling crisis. Never before had honoring the “full faith and credit of the United States” been used as a political bargaining chip. But in 2011, Republicans initially refused to raise the debt ceiling as had always been done. A last-minute fix stopped a U.S. default from setting off a global economic panic — but not before the stock market plunged, consumer confidence fell through the floor and Standard & Poor’s lowered America’s credit rating, costing taxpayers billions.

The world was stunned, but Republicans who knew better decided to treat the situation as an unfortunate incident rather than as a portent of future trouble for their party. The “falling rock zone” signs were gone.

5) The Republican convention in Cleveland. It had become increasingly clear that the nominee’s racial and ethnic slurs were jeopardizing their own candidacies — that Trump was tearing conservative principles to shreds. So why was Ben Sasse of Nebraska the only one of the Senate Republicans to say that Trump was unacceptable?

It shouldn’t be too shocking that Trump would later attack an American Muslim family that lost a son fighting in Iraq. And what kind of naive faith in Trump led House Speaker Paul Ryan to assume that The Donald wouldn’t go after him, even after he had compromised himself by endorsing Trump?

Some say Trump’s trying to blow it. Some say he’s just psycho. Again, all that was said before he became the standard-bearer for the Republican Party.

In any case, the downward spiral didn’t start with Trump’s altercation with the gold star parents. It didn’t even start with Trump.

The road to this debacle was being built long ago. Whether it leads to a huge pothole that can eventually be filled or a cliff with no guardrails remains to be seen. These are disquieting times for Republicans and everyone else.

Froma Harrop is a syndicated columnist. Follow her on Twitter @FromaHarrop. She can be reached at fharrop@gmail.com.