WASHINGTON (MarketWatch) — A petition on the White House’s web site calling for charges to be filed against 47 Republican senators who sent a letter to Iran’s leaders has garnered more than double the signatures it needs to draw a White House response.

The petition, on whitehouse.gov, was filed Monday and had 214,178 signatures as of mid-Thursday morning. To require a response from the White House, petitioners must secure 100,000 signatures within 30 days.

Some Republicans admit they were caught off guard by the backlash to the letter, which warned Iranian leaders against a nuclear agreement with President Barack Obama. Politico reported Sen. John McCain of Arizona, one of the signers of the letter, said Republicans should have given it closer consideration. Many Republicans endorsed the missive during a Senate lunch a week ago, and it was released Monday.

“Everybody was looking forward to getting out of town because of the snowstorm” last week, McCain said.

The letter drew blistering responses from Democrats, with Secretary of State John Kerry calling it a “stunning” breach of protocol. It was drafted by Sen. Tom Cotton of Arkansas, a freshman Republican.

Critics have dubbed the lawmakers the 47 traitors, with “#47Traitors” a hashtag on Twitter. The word “traitor” doesn’t appear in the petition, but it may as well: It charges that the senators committed treason by breaking the Logan Act, a 1799 law that forbids unauthorized citizens from negotiating with foreign governments. Legal experts, The Wall Street Journal writes, say the law is out of date and any prosecution likely wouldn’t get anywhere in court.

Yet the letter has clearly hit a nerve, as evidenced by the number of signatures and outrage on social media.