Vinaya Rule which prohibits on engaging in political activities
Bikkhu can advise laymen about  politics, for the example, see "Conditions of a Nation's Welfare" in mahāparinibbānasutta. 

And saṅgha means "group of bikkhu".

Another, all virtual (sīla), keeping-sīla (ethic) and avoiding-sīla (precept), are politic because of "10 purposes of monastic legislation:for the lastingness of the true doctrine", so all advising about physical action &amp; speech are politic, too.

However, bikkhu maybe offense vinaya, if the advising or action is wrong, conflicted with vinaya, such as ordering to kill or ordering to stole, etc.