Bob Inglis is a former Republican representative from South Carolina. He compiled a conservative record in the House, where he was a member of the Judiciary Committee and voted in 1998 to impeach President Bill Clinton.

But Inglis deviated from conservative orthodoxy in a couple of instances, including his acknowledgment of the connection between carbon emissions and climate change. He was defeated in a 2010 GOP primary by Trey Gowdy, who ran as a conservative purist.

Last week, Inglis tweeted that if President Donald Trump were a Democrat, House Speaker Paul Ryan would be “inquiring into impeachment” over Trump’s efforts to thwart the investigation into his Russia ties.

I spoke with Inglis, via e-mail, over the weekend. Here is a lightly edited transcript.

Q: I’m interested in how your Clinton history informs, or doesn’t, your perspective on questions about President Donald Trump’s actions regarding Russia and the investigation into his campaign and business ties. Looking back, was it a good idea to impeach Bill Clinton?

A: In retrospect, the underlying substance of the Clinton matter seems far less consequential that what we are dealing with now. Clinton had sex with a White House intern. He got impeached for lying about it as he tried to cover it up. Richard Nixon participated in a burglary. He nearly got impeached — resigning instead — for obstructing justice in an attempt to cover it up.

The matter involving President Trump goes to the heart of our republic: a hostile power attempted to influence the 2016 election. As former FBI director James Comey said several times in his testimony last week, if any Americans participated in that attack, it is a very big thing.

Q: That casts Trump’s situation as the most egregious. But impeachment is a dramatic step with ugly fallout. In retrospect, was it worth impeaching Clinton?

A: No.

Q: Does what we know so far of Trump’s actions regarding Russian interference and potential obstruction or abuse of power cross an impeachment threshold? Don’t we need more information?

A: We need more information. And all of us, Republicans and Democrats and independents, should be ready to support a vigorous investigation with no minimising of its import. Senator Marco Rubio, for example, should not have downplayed the import of the word “hope” in the directive President Trump gave to Director Comey to drop the Flynn investigation. Yes, Senator Rubio, “hope” can be a threat: “Nice car you got there, Senator. Hope nothing bad happens to it while you’re having dinner inside that restaurant.”

Q: Republicans — Rubio seems typical — are still very much in defensive mode, seeking to limit damage to the President. Republicans in the House, in particular, would surely bury any investigations into Trump if they could. Why and how would that defensive posture change?

A: Things will change for Republicans when we convince Trump supporters to be thankful for where we are and hopeful for the future. As it is, we’ve been mimicking Trump’s resentments. We’ve embodied his fear of the future, looking back with him and them to some good old days that never existed. Those Trump supporters comprise perhaps 38 per cent of the American people. They’ve been captured by his message of grievance. They are the dominant force in Republican primaries. They are the reason that Senator Rubio, for example, adopted a minimising, dismissing and excusing mode in his questioning of Comey. That 38 per cent prevents Republicans from pursuing a range of things — from co-operating with a full-bore investigation of Russia’s attack on our election, to crafting workable solutions on healthcare, to working on free-enterprise solutions to climate change.

The 38 per cent is driven by Fox & Friends’ elevation of commercialism over journalism, by the populist demagoguery on talk radio, by the ossification of the editorial pages of The Wall Street Journal and by the funding of the Koch brothers. That 38 per cent can kill you in a Republican primary, which is why elected Republicans are terrified of those voters. Ultimately, they will kill the Republican Party itself, and people who would have been open to conservative solutions will be driven away from the GOP for a decade or more.

Q: So do you believe Trump’s support among the congressional GOP is solely a function of that core group of Trump voters? That without those voters the Congress would be moving to aggressively investigate Trump and potentially remove him from office?

A: If not for that 38 per cent, congressional Republicans would be pursing the Russia investigation aggressively. If some connection were found between Trump and the Russian attack, congressional Republicans would impeach him.

After that, we could develop policies to address the legitimate concerns of the 38 per cent and others — globalisation, automation, the impending decline of the car and its effects on suburban lifestyle, and the rapid pace of cultural change.

Q: So you think Republicans would impeach Trump if there were proof of collusion? What about anything short of that standard? (For example, abuse of power or obstruction of justice.) Given partisan polarisation and the GOP’s interest in self-protection, wouldn’t it take an almost worst-case scenario for the party to abandon Trump?

A: Trump’s personal collusion with the Russians, if proven, would cause Republicans to remove him from office. If Trump didn’t personally collude but sought to protect those who did — family members or campaign folks — removal would depend on the egregiousness of the collusion. If it were egregious, I think they might remove him.

Q: When you talk with former GOP colleagues, do they register Trump as a danger to democracy and threat to US national security? Or do they simply view him as an unconventional politician in generally benign ways?

A: When I talk with them, it’s apparent that the concern is with the Trump voters more than with Trump himself.

Q: Meaning that they think Trump himself is a viable, functional president? Or are you saying that they think otherwise but fear the wrath of his voters?

A: Without a doubt, the latter.

•Francis Wilkinson writes editorials on politics and US domestic policy for Bloomberg View. He was executive editor of the Week. He was previously a national affairs writer for Rolling Stone, a communications consultant and a political media strategist