WASHINGTON — There’s much speculation about Russian motives for intervening in Syria. The root answer lies in the timing.

Vladimir Putin, the Kremlin boss, finally decided Syrian leader and Moscow ally Bashar Assad was in danger of losing control of Damascus, the capital of the civil-war ravaged nation.

That, in turn, would have crushed a key Russian foreign policy objective — keeping Syria together as a unitary state and maintaining the Russian foothold in the Middle East.

“Assad has not been doing well for a long time, so that leads me to believe they (the Russians) saw something lately that made them think things were getting considerably worse, and they had to intervene,” said Eugene Rumer, director of the Carnegie Endowment Russia and Eurasia program.

Holding together the status quo has played heavily in Kremlin foreign policy reaching deep into the past. And the logic of Mideast and North African developments — the centrifugal spinning apart of Iraq and Libya, for example — was deeply unnerving to Moscow.