Evangelical churches in Cuba are collecting signatures to petition against a constitutional amendment that would redefine matrimony as gender neutral, allowing for gay marriage.

The campaign is particularly strong for a non-governmental political campaign. Cuban evangelical leaders expect 500,000 signatures against the amendment, called Article 68, reported Reuters.

Cuban Evangelical League Church President Alida Leon Baez told Reuters there would be consequences if the amendment was signed into law.

“If the topic of matrimony is not modified in the constitutional project, we will all vote against it,” said Leon Baez. “If this is approved, our nation is going to total destruction.”

LGBT activists have been running a counter-campaign on social media, but they argue the government doesn’t recognize independent activists. This means they can’t run larger campaigns like Cuba’s churches.