It was supposed to relieve a headache for Australian Prime Minister Malcolm Turnbull, but a postal vote on whether to legalize same-sex marriage has awakened interest in politics among young voters who could ultimately turf him out of office.

There had been strong calls from the public for Australia to become the 25th nation to permit gay marriage, a move that Turnbull supports, but more conservative members of his Liberal Party oppose.

Holding a wafer thin parliamentary majority of just one seat, Turnbull opted to call a non-binding ballot as it was politically the least risky way of putting a highly emotive issue on the agenda.

The fierce national debate that ensued persuaded many young Australians to take a far greater interest in politics than they had before.

And while that might help Turnbull make the progressive, liberal amendment to the marriage law that he personally supports, it could cost him in the long term as there is a strong likelihood that the new generation will lean toward the center-left Labor Party rather than his Liberals.

“The issue of same-sex marriage has given the opposition a massive advantage in encouraging more young people, who are far more likely to vote for Labor, onto the electoral roll,” said Simon Banks, one-time chief of staff to former Labor Prime Minister Kevin Rudd.

Young Australians previously have been tardy about registering to vote, knowing that once they do the law requires them to cast their ballot or face a fine of A$110 ($86). But the gay marriage issue persuaded more to get their name on the electoral roll. Read more via Reuters