When did U.S. political parties first develop party platforms at their nominating conventions?

The first party platform was negotiated by the Democratic Party for the 1840 election.

Who were Adlai Stevenson’s running mates in the 1952 and 1956 elections? John Sparkman in 1952 and Estes Kefauver in 1956, were Adlai Stevenson's running mates in the 1952 and 1956 elections. Stevenson lost both times to Dwight Eisenhower and his running mate Richard Nixon.
Who was the first female to hold a post in the U.S. Cabinet? The first female to hold a post in the U.S. Cabinet was Frances Perkins. She served as Secretary of Labor under Franklin D. Roosevelt from 1933 to 1945.
When was New York City the capital of the U.S.? New York City was named the capital of America in 1788 and remained so until 1800, when Washington, D.C. was so named.
What countries today have nuclear weapons? Eight countries are currently known or suspected to have nuclear weapons. They are: China, France, India, Israel, South Africa, the Soviet Union, the United Kingdom, and the United States.
Why does the phrase Swan Song mean a farewell or goodbye? The phrase Swan Song refers to ancient legend. It was thought that the swan, silent throughout its life, sang aloud in its final minutes.
When was the U.S. Navy established? An American "Continental Navy" was established by the Second Continental Congress on October 13, 1775. It was disbanded after the War of Independence, in 1784. The first U.S. Navy was not established until…