Despite Secretary of State John Kerry's best efforts to broker a ceasefire, America's worst enemies are continuing to slaughter each other in Syria by the thousands.  Here are some of the groups involved:

Hezb'allah: Hezb'allah is a radical Shi'ite militia that controls much of Lebanon.  Before the war, they launched rockets and terrorist kidnapping raids against Israel; before that, they were responsible for the murder of 241 American soldiers in Lebanon.  But they have no time for that now that they are engaged in the war in Syria.  Tragically for them, about a third of the soldiers Hezb'allah has sent into Syria to fight for Assad are said to have been killed (about 1,500), and even more (5,000) wounded.

Iraqi Shi'ite militias: Iraq has sent radical Shi'ite militias in to Syria, also to fight for Assad.  Allied with radical Iran, their specialty is the beheading of opponents, mutilation of bodies, and torture and rape of their opponents.

Iranian Revolutionary Guards: The Revolutionary Guards are the most radicalized soldiers in the Iranian armed forces, and they fight for Assad.  These are the guys who captured and humiliated American sailors in the Persian Gulf and the same guys who regularly stage mock attacks on our warships.  Tragically, nearly 700 Revolutionary Guards have been killed in Syria, some of them quite senior:

In June, at least a dozen members of Iran’s Islamic Revolutionary Guards Corps — some of them high-ranking — died in battles near Aleppo, and around that time some regular Iranian Army troops headed for Syria.

Syrian soldiers: The Syrian soldiers are, of course, also fighting on behalf of Assad.  Before Syria was distracted by the war, it was busy building a nuclear power plant, presumably to make nuclear weapons (until Israel destroyed it), and arming Hezb'allah in Lebanon to make attacks on Israel.  With the war, Syria has been severely weakened and hasn't had any resources to commit externally.  More than 100,000 Syrian soldiers have been killed thus far.

Russia: After officially withdrawing from Syria last spring, Russia's forces that were no longer there stepped up their bombing attacks, trying to turn the city of Aleppo into one big parking lot.  Before the war, Russia could be counted on to supply Syria with weapons, which could in turn be supplied to Hezb'allah in Lebanon to attack Israel or commit acts of terrorism against the West, but with the war going on, those efforts have been diverted.  Sadly, dozens of Russian soldiers have been killed in Syria.

Afghan Shi'ites: Iran is said to have sponsored up to 20,000 Afghan Shi'ites to fight in Syria.  Sadly, more than 300 have died in the conflict.  If not for the conflict, they would be at home in Afghanistan, perhaps fighting Americans or growing poppies for opium.

Palestinians: Palestinians have come to Syria to fight for Assad and against him.  So far, at least 800 Palestinians fighting against Assad have been killed and 635 Palestinians fighting for Assad have been killed.  Without the war, the Palestinians would undoubtedly be focused on making terrorist attacks against Israel.

Moderate rebels: Moderate rebels are called "moderate" because they are moderate in number.  Mostly they have "boots on the ground" on CNN and BBC interviews, less so in Syria.  The U.S. spent $500 million to train 50 of them; 45 deserted.

Al Nusra Front: Al Nusra is the radical Sunni group that recently renounced its affiliation with al-Qaeda.  There is no word on whether they have also renounced their policy of kidnappings and executions of civilians.

ISIS: Then there is the Islamic State, or, as Obama calls it, "Daesh," or "Definitely not the Islamic State."  ISIS is like a vacuum cleaner, drawing radicals from all over the Muslim world to come and fight in Syria and Iraq.  So far, more than 50,000 of them have been killed for their efforts.  If not for keeping busy in Syria and Iraq, there is no doubt they would turn their attention abroad to other efforts.

It's very sad that this cycle of violence is continuing, in violation of international law.  The conflict between Sunnis and Shias is undoubtedly the root cause of violence in the Middle East.  We can only hope that someday this conflict ends, so the combatants can resume their lives of peace and interfaith tolerance.

Ed Straker is the senior writer at NewsMachete.com.