Former Greens leader Bob Brown and Greens senator-in-waiting Andrew Bartlett spent several years in the Australian Senate making a noise about a constitutional rule which has now crippled their party.
The federal Greens party is facing an extraordinary crisis after both its co-deputy leaders, Scott Ludlam and Larissa Waters, were forced to resign from parliament after finding out they were dual citizens of New Zealand and Canada respectively.
Ludlam and Waters — touted as future leaders of the Greens — fell foul of Section 44 of the constitution which, among other specific criteria, doesn't allow MPs to hold dual citizenship.
The glaring oversight led to overseas-born federal MPs falling over themselves on Tuesday to assure everyone they had renounced dual citizenship.
"I've got members and supporters who I suspect will be feeling like many of us - they'll be frustrated, they'll be disappointed," Greens leader Richard Di Natale said on ABC's 7:30 program.
"Many of our members, supporters and indeed, voters, will be reeling right now."
But the Greens should be well versed in the particulars of Section 44, as two of its most senior members spent many years trying to change it.
In a stunning coincidence, the man set to take Waters' Queensland Senate seat, Andrew Bartlett, repeatedly called for "urgent" change to Section 44 during his time as a senator for the now defunct Australian Democrats party.
In 2005, Bartlett sat on the Legal and Constitutional Affairs committee and added his own specific recommendations about the eligibility of dual citizens to run for parliament in a report into changes to Australian citizenship.
"Finally, I believe it is becoming more and more urgent that an effort is made to make the necessary change to our constitution that prohibits dual citizens from running for parliament," Bartlett wrote.
"Dual citizenship is part and parcel of modern society and certainly of Australian society.
"I believe we are short changing ourselves as a nation if we prevent dual citizens from becoming a member of parliament."
In a speech to the Senate in 2007, Bartlett again called for urgent change to the constitution because of the large number of people in Australia who hold dual citizenship.
"(If) we have nearly one-quarter of our community overseas-born and a significant number on top of that whose parents are overseas born, there is a fair chance that the number of dual citizens we have is actually greater than the 20 per cent that is often used as an estimate," Bartlett said.
"The more we go down this path — and it is a path that I support us going down —the more we are coming up against a major impediment in our constitution, which is that anybody who is a dual citizen is precluded from running for the federal parliament."
Bartlett was defeated at the 2007 election and subsequently joined the Greens, climbing through the party's ranks to become Queensland Greens party convenor and number two on the Greens 2016 senate ticket behind Waters.
Former Greens leader and party founder Bob Brown was the other senator who was well aware about the details and potential pitfalls of Section 44 of the constitution.
In the wake of a High Court decision about the disputed election of a candidate at the1996 election, Brown successfully passed a motion in the Senate calling on the government to come up with a proposal that would change Section 44.
"That the Senate notes... section 44 of the constitution impedes many Australian citizens from standing for Parliament, including citizens holding dual citizenship, public servants and certain others who may be holding an office of profit under the Crown; and calls on the Federal Government to respond with a proposal for amendment," Brown's motion read.
Brown's advocacy on the issue didn't stop there.
Two years later, Brown introduced a bill called Constitutional Alteration (Right to Stand for Parliament Qualification of Members and Candidates) Bill 1998, which didn't pass the Senate.
Brown re-introduced the bill in 2003. It failed an absolute majority vote of both houses of parliament, which was the threshold required because it was an amendment to the constitution.
It didn't go away; a few months later in October 2003, another motion was passed to call for the amendment to allow dual citizens to run for parliament.
The motion was moved by senator Andrew Bartlett.