So while the war in Syria has provided Mr. Putin with a Middle Eastern foothold, his interests are not limited to Syria. He has already forged a working strategic partnership with Iran and, increasingly, a common understanding with Turkey.

And the Trump administration has provided him with the means to dream even bigger — a chance to lead a broad-based alliance with countries leery of the Saudi-American axis. This includes not just Qatar and Turkey, which are Sunni, but also Shiite Iran and its regional friends, as well as Shiite-majority Iraq and potentially Oman (whose majority practices a third form of Islam, Ibadi).

Together, those countries could wield significant power in the region and in global energy markets. Their coalescence would also raise the prospect of bringing together Shiite and Sunni populations behind a future for the Muslim Brotherhood, a surviving precursor of the wide variety of today’s political forms of Islam and still a force in much of the Arab world. While that movement remains widely popular in the region, it is anathema within the Saudi-American axis.

With prospects like that, Mr. Putin’s star in the region is clearly ascendant.

How did this happen? Mr. Trump’s open support of Saudi Arabia and its allies against Qatar was taken as a warning to Turkey, Iraq and Oman that they too would face ostracism by the Saudis — and America — if the Saudis were to accuse them of supporting extremism or getting too friendly with Iran.

Indeed, Qatar and Turkey have differed with Washington and Riyadh on how to confront Islamic State forces while helping Syrian rebels try to topple President Bashar al-Assad, whom Russia and Iran protect. Despite having criticized Iran’s role in the conflict until now, Qatar and Turkey have both begun to see Syria through the lens of their resistance to the Saudi-led bloc. This does not bode well for hopes to de-escalate the Syrian war; it is much more likely to solidify a Russian-led alliance.

Washington may hope that there is a path to quick mediation and reconciliation. But Qatar is not about to wave the white flag. Indeed, its immediate reaction was to seek — and get — support from Turkey and Iran. Turkey’s president, Recep Tayyip Erdogan, pushed through his Parliament a bill that lets Turkey deploy troops in Syria. Iran began airlifting food and gave Qatar access to three Iranian ports to circumvent the Saudi-American blockade.