The phrase "strange bedfellows" means two people (or groups) of totally different qualities and principles working closely together, which is odd (strange) to see. 

Strange bedfellows指两个在性格、处事原则等各方面完全不同的两个人或组织密切合作的情况。这种合作看上去就很奇怪。我们可以称之为“怪异盟友”或者“同床异梦的伙伴”。

 

We often hear "politicians make strange bedfellows." That means politicians will do anything to succeed, ready to try all means and measures, fair or foul¹, including working with their hateful political enemies if they have something to gain from such an alliance.

我们经常会听到“政客们都会有怪异盟友”这样一句话，说的是政客们为了达到自己的目的会做出任何事情，不择手段，如果能让自己获利，他们也能跟自己憎恶的政敌联手。