Western powers should “do more” to “help the opposition” in Syria said British prime minister David Cameron, even if there isn’t an international mandate for intervention.

The European leader described himself as a “conservative liberal” in an interview with Newsweek that was published while Cameron was in the United States for a three day visit.

He said to struggle with the tension between the two ideologies when it comes to foreign policy.

You get the instincts of a conservative — skeptical and worried about grand plans to remake the world — but liberal in that you want to see the spread of democracy and rights and freedoms that we enjoy here.

Cameron cited NATO’s 1999 intervention in Kosovo as an example of a situation in which the “responsibility to protect” and imperative “to save lives, to stop slaughter” trump the need for a United Nations resolution.

I’ve always thought it odd the argument that because there’s a Russian veto, suddenly all the other moral arguments are washed away. I don’t believe that.

With France, Cameron’s Great Britain was the driving force behind the intervention in Libya last year which was sanctioned by the Security Council.

China and Russia are reluctant to vote for a similar adventure in Syria because, as they see it, NATO airpower didn’t just protect civilians in Libya but actively helped topple the regime of Colonel Muammar Gaddafi.

In Libya, Western powers had little reason to want to see Gaddafi gone. He was hardly a threat. In Syria, by contrast, they have a clear interest in removing President Bashar al-Assad from office. He is Iran’s only Arab ally — a country that finances terrorism and is enriching uranium, possibly for the purpose of developing nuclear weapons.

An intervention then would be “to act in a way that is both morally right but also in your own national interest,” as Cameron put it.