The Patriots needed help from France and Spain to win the war. France wanted to get back at the British they have been enemies for a long time now, so they saw an open door thru the Patriots so they did everything in their power to help the Patriots win. You must the have public opinion everyone needs to be on the same page. Declare Independence from Britain must have everyone hearts and minds. The only way you will do that is to have the book from Thomas Paine called Common Sense, you must spell it out for people.
It’s great to have an army but you must give the people something to fight for and Thomas Paine does that in the book that he wrote. Also, while writing the Declaration of Independence. This allowed the Patriots to reduce Loyalist efforts to help the British. Americans prevailed due to their Christianity and the circumstance that they were fighting for something they believed in. They did win the support of France. When war erupted in 1775, it seemed clear that Britain would win.