US sanctions on Russia bring political gain before midterms

America's sanctions on Russia have been a long time coming.

It took a while, according to a senior state department official, for the US to do its "homework" on the Skripal attack in March.

But some biting sanctions have arrived, and more are coming if Russia fails to convince America that it will never use chemical weapons again.

Despite Donald Trump's history of charting a course often at odds with his own departments and agencies, especially on Russia, this time it is pretty safe to assume the president will toe the line.

In part that is because there is political gain to be had here.

The midterms are coming.

A strong, decisive president, wielding power against adversarial nations like Iran and Russia, will play well with the Republican base.

:: US imposes sanctions on Russia over Skripal poisonings in Salisbury

It is also useful that the new sanctions come at a time when Mr Trump is facing ongoing criticism that he is too close to Moscow, and as the constant drum beat of special counsel Robert Mueller's collusion investigation continues.

Separately, there is also a broader issue relating to the necessity of dealing with existential threats.

It is just common sense that most countries want to make the consequences for chemical weapons use very unpleasant.

Whatever may or may not be going on between Mr Trump and Mr Putin, that includes America.