The 5 way bar fight has again come to a head. The conflict explosion follows the incapacity of Putin to manage his multiple conflicts on multiple fronts any more.
US isolationists won't get the isolation they sought via Trump's election win.
A US do nothing stance won't just lead to a ( same old) war continuance in the ME. Without knowledgeable and considered immediate action by BOTH the Biden and Trump administrations the following outcomes become likely.
1. Syria falls under control by Al Qaeda offshoot the HTS front. HTS leader Abu Muhammad al-Jolani previously ran the Nusra Front and will likely impose a harsh version of Sharia Law. This would lead to large numbers of refugees heading for Europe and the US via Lebanon.
2. Erdogan controlled Syrian National Army fighters remain primarily engaged against a US supported Kurdish alliance in Northern Syria.
3. Iran will likely intervene on behalf of Alawite and Shia populations and to support its own interests in Lebanon. Hezbollah may have to forget about antagonising Israel in current circumstances.
4. Iran's relationship with the Kurds isn't great due to the presence of Kurdish separatists in Iran.
5. ISIS has a residual presence in Eastern Syria and will likely fill any vacuums created by the chaos.
6. Chaos of war can easily spread into Iraq and elsewhere accoss the ME thus impacting oil supplies. Regimes mat topple.
The US can exert significant influence accross multiple parties ATM but this window can close quickly. My view (albeit unrealistic) is that Biden and Trump need to issue a joint statement which points to a Federative solution for Syria and which defines a pathway for getting there.
The Kurds will also pivotal to any solution. They are Sunni and progressive (not an oxymoron) and have capacity to work things out with all of the other groups. Nobody else does. The Syrian Kurds can retain their feminist, Socialist version of Islam BUT will need to dump any direct or covert links to the Turkish PKK. Erdogan will expect peace on his own terms. Only the US can negotiate such an outcome.
Trump must consider a General with direct ME field experience in Syria and Iraq as a Secretary of Defence NOW. A former brigadier or full colonel with deep intelligence knowledge of Syria, Iraq and Lebanon would be ideal.