The conflict in Yemen is about to claim yet another casualty. The Muslim Brotherhood affiliate al-Islah party is in retreat across the south, and pressure mounts in both Mareb and Taiz. The near monopoly held by Islah within the legitimate government over the past seven years has collapsed as the party is increasingly blamed for years of failures against the Houthi movement. Rivals accuse the party of apathy and widespread corruption, along with ties to terrorist elements and secret cooperation with the Houthis. Islah’s decline undoubtedly began in August 2019 as tensions escalated in the inte…