This lays the basis for a fundamental change in how Russia views its relationship with the United States. Whereas previously President Trump appeared to be implementing Russian policy for the US, whether consciously or unconsciously, the Syria strikes suggest that he cannot be relied on to do so consistently. In demonstrating clearly what conduct is unacceptable to the United States, Trump has departed completely from practice by the previous administration. President Obama's predictable disinclination to enforce red lines or respond to Russian assertiveness invited Moscow to ever more blatant hostile activities. Now, Russia will be forced to at least consider the possibility that its actions may have costs and consequences imposed by the United States.
In this way, the use of military force against Syria provides a degree of reassurance for other states around the world whose security relies on the United States being prepared to counter Russian offensive moves. To some small extent it does resolve the doubt over whether the United States will now be willing to resort to force in the defence of third parties' interests. In particular, despite the restraint displayed by the United States in warning Russia of the impending strikes in order to avoid Russian casualties and the risk of direct conflict with Russia (but also allowing Russia to warn Syria and minimise damage), the speed of response by Washington may have got inside the Kremlin's military and political decision loop, and achieved a degree of operational if not tactical surprise. There may have been restraint on both sides: it is suggested that Russia chose deliberately not to test its anti-missile defence systems in place in Syria against the incoming US cruise missiles.