A Republican presidential elector has become the first to announce that he intends to defect from Donald Trump when he casts his vote as part of the electoral college, vowing to try and block the president-elect from reaching the White House.

Writing in the New York Times, Christopher Suprun has declared that he will break ranks with his fellow Republican electors in Texas and cast his vote for a GOP candidate whom he deems to be more fit for highest office. He argues that under the electoral college system he has the constitutional duty to vote according to his conscience, not just according to party loyalty – and his conscience tells him that Trump is unfit for the presidency.

Citing the Federalist Papers, the historic documents that laid out the principles behind the electoral college system, Surprun, who as a firefighter was one of the first responders to the Pentagon on 9/11, says that each elector must decide whether “candidates are qualified, not engaged in demagogy, and independent from foreign influence … Mr Trump urged violence against protesters at his rallies during the campaign. He speaks of retribution against his critics.”

He adds: “I owe no debt to a party. I owe a debt to my children to leave them a nation they can trust.”

Suprun’s declared defection from Trump marks the first time that a Republican has broken ranks in this election cycle to become what is known as a “faithless elector”. Up to now only Democratic electors within states won by Hillary Clinton have expressed the intention to vote against party affiliation as a form of protest against Trump’s imminent ascendancy to the White House.

Until Suprun’s defection, seven of the 538 electors across the country had indicated that they intended to become faithless electors by breaking ranks with party affiliation. However, they were all Democrats within states won by Clinton.

Under the electoral system laid down by the founding fathers, US presidents are not chosen directly by the popular vote of the American people. Instead, they are elected indirectly by 538 electors who selected by the political parties within each state.

In contemporary America, it is widely assumed that the electors will simply vote according to their party affiliation in tune with which candidate won their state. Thus in Texas, which has been assigned 38 of the 538 electoral college votes, it was assumed that all 38 electors would vote for Trump who beat Clinton in the state by 52% to 43%.

However, one of the Texan electors, Art Sisneros, has already resigned from the state’s electoral college delegation on grounds that Trump does not satisfy his religious and moral principles. Now Suprun says that he will go further – he will show up on 19 December when the electoral college assembles in each state and actually cast his ballot against Trump, by writing in an alternative Republican candidate of the likes of John Kasich, the governor of Ohio.

“I believe electors should unify behind a Republican alternative, an honorable and qualified man or woman such as Gov John Kasich of Ohio,” he writes.

The idea that several of the 538 electors might take it into their own hands to attempt to sway the outcome of an election that involved more than 127 million voters has proven to be quite contentious. Some have taken the view that it is in itself a deeply retrograde and undemocratic step; others have lauded it as exposing the implicit undemocratic nature of the electoral college itself that imposes an indirect barrier between presidential candidate and people.

Either way, few expect that this year’s rebellion of electors will have any definitive impact on the outcome of the race. Though it looks like being historically large in number, it is most unlikely to tip the balance of electors from Trump to Clinton, who currently hold 306 to 232 electoral votes respectively.

Suprun’s breach with convention has been brewing for some time. In August, he told Politico that he was so worried about Trump’s candidacy that he was contemplating the move.

His defection was welcomed by fellow faithless electors on the Democratic side. Bret Chiafolo, a cofounder of the group known as Hamilton electors who believe members of the electoral college must vote according to their conscience as set out by the founding fathers, said that Suprun was acting as a true patriot.

“He is showing that there are patriots of all stripes left in this country, that if all sorts of people can set aside their party divisions we still have hope of saving this country from a demagogue,” said Chiafolo. He is an elector in Washington state, which was won by Clinton, but he intends to vote against her in a protest move directed firmly against Trump.