Intelligence officials have calculated that Tehran does not have full control over its proxy groups in the Middle East‚ including those responsible for attacking and killing U.S. troops in recent weeks‚ according to two U.S. officials familiar with the matter. The Quds Force — an elite branch of Iran’s Revolutionary Guard Corps — is responsible for sending weapons and military advisers as well as intelligence to support militias in Iraq and Syria as well as the Houthis in Yemen. The groups...