Airstrikes have failed to suppress the Houthis, who remain entrenched in northern Yemen’s mountains. Only a ground invasion of their strongholds can uproot them for good. By Hugh Fitzgerald, Frontpage Magazine The qat-chewing, rifle-toting Allahu-akbaring Houthis of Yemen whose attacks on international shipping have forced ships that used to use the Red Sea-Suez Canal route to deliver cargo from Asia to Europe, to instead take a much longer rout…