If you want to get a Nobel Peace Prize, your best shot comes from committing war crimes or crimes against humanity. This is not a pathway for the low-level soldier who kills a few POWs or women and children. You have to think big to get the Nobel Peace Prize. I popped up the list of Peace laureates at Wikipedia. Here are some of the historical highlights. Forgive me if I don't list every single war criminal, and detail all their war crimes. That would require a book.
United States President Theodore Roosevelt received the prize in 1906 for arbitrating an end to the Russo-Japanese War. But Roosevelt was a life-long war monger. He was one of the architects of the Spanish-American War. After that war was over he was President while the U.S. waged a genocidal campaign against the independence movement in the Philippines (which became a U.S. colony and base for further military intervention in Asia). He originally encouraged the Japanese and Russians to fight, and he allowed the Japanese to grab Korea in return for their not challenging U.S. rule of the Philippines. He wanted to end the Russo-Japanese War while the Japanese were still ahead because he believed Russia was the greater threat to the U.S. in Asia.
Woodrow Wilson, another United States President, was an avowed racist who kept African-Americans in legal chains. Even Theodore Roosevelt attacked him for being a racist. He won the Presidency in 1912, then in the 1916 election promised the American people to keep us out of the war (World War I) in Europe. After the war he did help create the League of Nations, but he established it on a racist basis, personally blocking a Japanese proposal to treat non-white nations on an equal basis with white folk.
You probably have not heard of Cordell Hull, Franklin Delano Roosevelt's Secretary of State who helped create the United Nations. Cordell Hull did everything he could to force Japan into fighting the U.S. in World War II. The United States had ten times the industrial capacity of Japan, so the outcome of a war was never in doubt. FDR wanted to prevent Japan from enabling Asian nations to gain independence from the United States and the European powers. [See also 1937 to 1940: U.S. Economic and Proxy War with Japan]
Henry Kissinger got the Nobel Peace Prize in 1973. He got it for negotiating an end to the War in Vietnam. Of course, that was a U.S. war of aggression. Negotiations should not have been necessary. Kennedy, Johnson, and Nixon plus their leading henchmen should have been tried and sentenced like the Nazis at Nuremberg. How many people, mainly Vietnamese, died while Kissinger spent four years negotiating? And why give the prize to Kissinger instead of President Richard Nixon, his boss?
On the other hand, the committee does give Peace Prizes to genuinely good people: Jane Addams, the American Friends Service Committee, Martin Luther King, Doctors Without Borders, etc.
Does inheriting a war make you a war criminal? Only if you keep prosecuting the war.
My criteria for giving a peace prize to a United States President is this: when one withdraws all U.S. troops from non-U.S. territory, she'll deserve a prize. If she prosecutes past U.S. Presidents, generals, and leaders of Congress for their war crimes and crimes against humanity, I might agree that peace and justice have finally come to America.