"I think it's necessary to define in the Constitution what is innate to our people, what is in the tradition of our people and understanding of marriage," the opposition leader said on Croatian Radio.
He voiced confidence that a high percentage of voters would say 'yes' at the referendum, but said "it's not good that we have to put some obvious and fundamental things in the Constitution."
Responding to the interviewer's remark that the government had not announced that it would change the legal definition of marriage, Karamarko said citizens had been "under attack by the terror of relativity" because of the introduction of health education in schools. He said he believed that allowing same-sex marriage would have been the government's next step.
The collection of signatures for the referendum "was a spontaneous response and has its logic," he said, concluding that "many things will be different" after December 1. "Nobody will be able to easily play with what is innate to this people any more."
Karamarko said the worldview divisions in society were caused by the government, "which thinks it will bring something revolutionary to Croatia. We don't need such re-education. We need reforms, an economic revolution and job creation."
He has still not signed a referendum initiative on the Cyrillic script, reiterating that the HDZ bodies would decide about that. He said the HDZ "supports the Initiative (for the Defence of a Croatian Vukovar) in those activities in which it advocates respecting the law." He reiterated that putting up bilingual signs in the eastern town of Vukovar was contrary to the constitutional law on national minorities' rights.
Karamarko also reiterated that there had not been two but one column in the Vukovar Remembrance Day procession last Monday, with 100,000 citizens in it. He said state officials could have joined that column had they really wanted to.
"Who can stop the president and the prime minister from joining that column? Some secret services are now being implicated. We don't need this," he said, adding that PM Zoran Milanovic's statement that no law was broken in Vukovar on that day proved that the state leadership had not been prevented from joining the procession.
"Had they been physically stopped, some law would have been broken," he said, concluding that "the people distanced itself from the government" on that anniversary.
Asked if it had been the HDZ's plan to provoke an early parliamentary election, Karamarko said: "We won't provoke anything. This government is the best destruction of itself because of inaction and ungainly conduct in many situations."
He said the government was not elected to impose topics such as marriage, parliament's sponsorship over the Bleiburg commemoration, or the European extradition law. "Nepotism is everywhere, every other minister is in conflict of interest," he said, adding that he could not see why the PM was saying that the state was in order.
Karamarko announced that the HDZ would organise an economic forum in mid-December at which the party would present sections of its economic programme.
Asked if economic or worldview topics would decide the next parliamentary election, he said "both, because the incumbent government has annoyed people in both areas."