In the US, the American Revolution is taught as a David and Goliath story of a small ragtag army of colonists taking on the British Empire and winning our freedom. That's not wrong, but we did have a lot of help. You have to wonder why the French, the Spanish, and the Dutch were so interested in American independence. The answer is clearer when you pull the lens back to see the conflict on a global scale.
In a global context, the American Revolution was largely a war about trade and economic influence—not ideology. France and Spain, like Britain, were monarchies with even less fondness for democracy. The Dutch Republic was primarily interested in free trade. The leaders of all three countries wanted to increase their nations’ trade and economic authority, and to accomplish that, they were willing to go to war with their biggest competitor—Great Britain.
To the French, Spanish and Dutch governments, this was not a war about liberty: It was all about power and profit. If American colonists won their independence, that would cause harm to British interests and open new trade opportunities in North America and elsewhere for those who allied themselves with the colonists.
An exhibit at the Smithsonian's National Museum of American History, The American Revolution: A World War, looks at the American Revolution through the eyes of the other world powers of the time. Read an overview at Smithsonian.