The "world" should be the United Nations, specifically the Security Council.
In 2005 the UN adopted the "Responsibility to Protect" which is "the idea that
sovereignty is not a privilege, but a responsibility. RtoP focuses on preventing and halting four crimes: genocide, war crimes, crimes against humanity, and ethnic cleansing.
The responsibility to protect can be thought of as having three parts.
A State has
a responsibility to protect its population from genocide, war crimes, crimes against humanity and ethnic cleansing (mass atrocities).
If the State is unable to protect its population on its own,
the international community has a responsibility to assist the state by building its capacity. This can mean building early-warning capabilities, mediating conflicts between political parties, strengthening the security sector, mobilizing standby forces, and many other actions.
If a State is
manifestly failing to protect its citizens from mass atrocities and peaceful measures are not working,
the international community has the responsibility to intervene at first diplomatically, then more coercively, and as a last resort, with military force.
Civil society organizations, States, regional organizations, and international institutions all have a role to play in the operationalization of RtoP. The authority to employ the last resort and intervene militarily rests solely with United Nations Security Council ..."
http://en.wikipedia.org/wiki/Responsibility_to_protect It is the responsibility of the UN (through the Security Council) to act if they determine that the actions of the Libyan government constitute "genocide, war crimes, crimes against humanity and ethnic cleansing (mass atrocities)."
Russia (or China) may veto Security Council action against Gaddafi. So be it, but make them do so on the record. If things go badly in Libya the responsibility will be clear. While the price will be high in terms of Libyan blood, the next time the world body has to choose between national sovereignty and human lives, their decision may be different because of the Libyan experience. If R2P is to ever be more than pretty words on paper, it will be up to the Security Council. Maybe not now, but someday.