The Declaration of Independence

As soon as 50% of your entire population support the Sons of Liberty, you can declare the independence of your colonies. Your Monarch will not be amused and will send the Royal Expeditionary Force to quell the insurrection. In order to gain independence, you must defeat the Royal Expeditionary Force by capturing or destroying nearly all of their land forces and by taking back any colonies they might have captured. You do not need to destroy the fleet.

At the declaration, colonies with strong support for the Sons of Liberty sometimes promote veteran soldiers at work there to Colonial Regular in preparation for the coming war. In the future, the European enemies of your Monarch may support your effort if you generate a sufficient number of Liberty Bells after the War of Independence has begun.