The red-green alliance is the increasing collaboration between radical progressive groups (the reds) and Islamists (the greens), in particular American organizations that identify with the Muslim Brotherhood ideology.

On September 21, 2021 the Israeli Government was stunned by the removal of $1 billion for Israel’s Iron Dome missile defense system from a bill—a move that was led by progressive legislators from the Democratic Party in Congress. Although the House of Representatives approved the funding with a huge majority two days later, this unprecedented event is the result of a fundamental change that Washington is undergoing and of the growing influence of ideological currents on American foreign policy in the Middle East and toward Israel.
https://jewishjournal.com/commentary/opinion/343507/the-red-green-alliance-is-coming-to-america/