When Russia first became involved in the ISIS war in Syria last month, US priorities began to shift dramatically, seeking to ensure that Russia’s war against ISIS was isolated and distinct from America’s own war, while predicting Russia would face a grim defeat.

Being hostile toward Russia is an end unto itself in US foreign policy, and something that’s been a focus for generations. With the Paris attacks bringing renewed focus to the ISIS war, and French calls for cooperation, President Obama is warning him away from any possible cooperation with Russia.

It’s not just a US fear that they’ll have to share the ISIS war with Russia, but a fear that, if they’re in the middle of a mutual war against ISIS it’ll make it a lot more difficult for European nations, particularly France, to agree to extend sanctions against Russia over Ukraine.

The sanctions were already a tough sell, with the Ukrainian civil war in a state of ceasefire since February, and the administration sees French calls for a “grand coalition” as nearing a rapprochement with Russia that the US desperately wants to avoid.

Railing against Russia about Ukraine and predicting a Russian invasion of Europe in general has been a centerpiece of US policy in Europe recently, and has served as a pretext for US deployments of troops into Eastern Europe. Though clearly they don’t want a war with Russia, officials seem to have a lot invested in keeping a Cold War-style level of acrimony going as long as possible.