HE DEMANDS "empirical evidence" when his anti-science crusades are challenged, but couldn't produce evidence of substance when his job was taken to court.

Even Pauline Hanson, who has not been terribly fussy about her colleagues, might have had moments of doubt about Malcolm Roberts.

She initially praised him as an engineer, a valuable injection of tertiary credentials and intellectual heft to the usual One Nation appeal.

And he praised himself in his First Speech on September 13 last year: "Like Socrates, I love asking questions to get to the truth."

However, he has ended his political career as anything but an intellectual powerhouse, and dismally short of Socratic excellence.

One Nation Senator Malcolm Roberts during the debate on the Media Reform Bill in the Senate chamber at Parliament House in Canberra, Thursday, September 14, 2017.
One Nation Senator Malcolm Roberts during the debate on the Media Reform Bill in the Senate chamber at Parliament House in Canberra, Thursday, September 14, 2017. AAP Image - Mick Tsikas

Senator Roberts has been a dithering pretender. He not only did not know whether he was a dual citizen, but whether he was a citizen of anywhere at all.

High Court Justice Patrick Keane yesterday ruled that when he nominated for the federal election last year Senator Roberts knew "there was at least a real and substantial prospect" he was a British citizen.

That would disqualify him under section 44 of the Constitution which rules dual citizens are ineligible for election.

As the second One Nation senator this year to be constitutionally unqualified to sit in Parliament - and the fifth so far from three parties - Malcolm Roberts has entered the history books, for reasons he had never foreseen.

Having quit full-time work to google climate change for eight years, he entered Parliament to bust wide open the global warning "scam" and the "corruption" of the CSIRO and NASA - declared without evidence.

He had fans among climate change deniers, but to others he was inexpert, reliant on conspiracy theories, and could bore for Australia in open company.

Coincidentally, what could be his last speech to Parliament was on September 13 this year - neatly a year after his first - when he spoke of his "quantitative, measured analysis of the Background Briefing radio program on ABC TV on Sunday, 17 July 2011."

He reported: "In that 50-minute program, there were 22 instances where the ABC created or implied misrepresentations by omission and/or made unfounded associations. There were 22 in 50 minutes."

He is a likeable man although his affability isn't enough to compensate for the tedium of listening to his quirky conspiracy revelations.

He was sincere if misguided, and it as more by accident than deliberate manipulation that he played Pauline Hanson, someone for whom too much adoration is just about right.

Finally, no one can show testimony to my belief in the enduring power of human nature more than the great Pauline Hanson," he said in his First Speech.

Even Senator Hanson appeared embarrassed as he continued: "She is a woman of great courage to whom I owe being able to stand here today.

"Pauline listens to understanding and is honest, courageous and persistent.

"Twenty years ago, Pauline, the Establishment ridiculed you. At the same time they quietly started implementing some of your policies."

Which could explain why moments of doubt never entered her appreciation of Malcolm Roberts.