My answer: America With victories coming in many wars including: The American Revolution, The Spanish-American War, The Mexican-American War, The Indian Wars, The Barbary Wars, The Philippine–American War, The Banana Wars, The Moro Rebellion, The Border War (Pancho Villa Expeditions), World War 1, World War 2, Cold War deserves a mention, The Korean War, Successful Operations in Libya, Panama, Grenada, Lebanon, Iraq, Kuwait, Haiti, Bosnia-Herzegovina, Kosovo, and the Philippines in a matter of 232 years. They are now the indisputable best military in the world and almost always have been at war with some entity since its creation. The only disputable losses the Americans have suffered have been The Vietnam War and The War of 1812. The US military has been everywhere from Russia to Tripoli to New Guinea and has bases in 63 countries and 250,000 troops worldwide. With the world's largest defense budget no other country comes close to the military power of the US.
I would have to say Germany comes in a close second. The HRE, Austro-Hungarian Empire (Maybe not so much), North German Confederation, Third Reich, and German Empire are all germanic influenced at the very least so I guess we'd group them all into one. Even though they have a longer history than America they have had a large bundle of losses especially in modern history.
