Nobody started it. There's too much at stake for anyone to start it, unless your one of the many individuals with nothing to lose who represent no government agency. Even the Iranians are smart enough not to start an all-out nuclear war once they get their nuclear stockpile up to snuff.
Maybe the most dangerous political figure is Kim Jong Il, who I suppose could, as he lay dying in old age and insanity, order a nuclear strike because fuck his country if he can't run it.
So, North Korea started it.
And the United States, Canada, Mexico, Panana, Haiti, Jamaica, Peru, the Dominican Republic, Cuba, El Salvador, Colombia, Venezuela, Honduras, Guyana, Guatemala, Bolivia, Argentina, Ecuador, Chile, Brazil, Costa Rica, Belize, Nicaragua, Bermuda, Bahamas, Trinidad & Tobago, Paraguay, Uruguay, Suriname, French Guyana, Barbados, Norway, Sweden, Iceland, Finland, Germany, Switzerland, Austria, Czech Republic, Slovakia, Italy, Turkey, Greece, Poland, Romania,
the United Kingdom, Albania, Ireland, Russia, Oman, Bulgaria, Saudi Arabia, Hungary, Cyprus, Iraq, Iran, Syria, Lebanon, Israel, Jordan, Yemen, Kuwait, Bahrain, Netherlands, Luxembourg, Belgium, Portugal, France, Denmark, Spain, India, Pakistan, Burma, Afghanistan, Thailand, Nepal, Bhutan, Cambodia, Malaysia, Bangladesh, China, South Korea, Japan, Mongolia, Laos, Indonesia, the Phillipines, Taiwan, Sri Lanka, New Guinea, New Zealand, Borneo, Viet Nam, Tunisia, Morocco, Uganda, Angola, Zimbabwe, Djibouti, Botswana, Mozambique, Zambia, Swaziland, Gambia, Guinea, Algeria, Ghana, Burundi, Lesotho, Mali, Togo, Niger, Nigeria, Chad, Liberia, Egypt, Gabon, Tanzania, Somalia, Kenya, Sierra Leone, Libya, Cameroon, Congo, Zaire, Ethiopia, Guinea Bissau, Madagascar, Rwanda, Qatar, United Arab Emirates, Mauritania, Monaco, Lichtenstein, Australia, and Sudan all finished it.
My apologies to the nations I forgot. :/