Is there any legal consequence in infringing a U.N. resolution? Let's say a U.N. resolution passes, but a country decides to infringe that resolution. What would be the likely consequences of such an action? What if a country that has veto power infringes it like the U.S., China or Russia? Since they have veto power, do they get off scot-free or is it more complicated than that?
Let's distinguish between UN General Assembly resolutions and UN Security Council resolutions. General Assembly resolutions are more accurately called recommendations, so for those, the answer is NO.
Security Council resolutions, on the other hand, are enforceable under Chapter VII of the UN Charter. Chapter VII exclusively deals with Action with Respect to Threats to the Peace, Breaches of the Peace, and Acts of Aggression.
Under Article 41, the Security Council may include "complete or partial interruption of economic relations and of rail, sea, air, postal, telegraphic, radio, and other means of communication, and the severance of diplomatic relations."
Should these actions prove ineffective or insufficient, under Article 42 the Security Council may take "such action by air, sea, or land forces as may be necessary to maintain or restore international peace and security. Such action may include demonstrations, blockade, and other operations by air, sea, or land forces of Members of the United Nations."