Sen. Barbara Boxer, usually in lockstep with the Obama Administration, took a step out of line on Monday by tacitly criticizing Secretary of State John Kerry’s likening Israel to an apartheid state. 

Boxer tweeted that any statement that likened Israel to apartheid “is nonsensical and ridiculous.” On Friday, Kerry said that Israel runs the risk of becoming “an apartheid state” if Israel doesn’t come to an agreement with the Palestinians. Boxer worked with Kerry on a climate change bill in 2009.

Democrat Nita Lowey of New York, ranking member on the House Appropriations Committee, tweeted: “Inflammatory rhetoric comparing Israel’s democracy to repugnant apartheid policy is irresponsible, inaccurate & counterproductive.”

Democratic Sen. Mark Begich of Alaska joined the chorus, saying:

Secretary Kerry knows as well as anyone that negotiating lasting peace in this region of the world is difficult but it’s not productive to express his frustration in this way. This remark also implies Israel should ignore the pact between [Palestinian President Mahmoud] Abbas and the Hamas. Last time I checked, the U.S. didn’t negotiate with terrorist organizations and we shouldn’t expect the Israeli government to either.

GOP lawmakers had already attacked Kerry for his comments; Sens. Ted Cruz (R-TX) and Marco Rubio (R-FL) and House Minority Leader Eric Cantor (R-VA) all expressed their disapproval. On Monday evening, Cruz went so far as to assert Kerry should resign from his job, saying:

I was convinced that as Secretary of State John Kerry would place what he considered to be the wishes of the international community above the national security interests of the United States. I fear with these most-recent ill-chosen remarks, Secretary Kerry has proven those concerns well founded. Secretary Kerry has thus proven himself unsuitable for his position and that before any further harm is done to our alliance with Israel, he should offer President Obama his resignation and the President should accept it.