As it marks the 250th anniversary of the Declaration of Independence, the United States should rededicate itself to its founding principles and to a strategy in the world that seeks to advance those principles.

As we approach the 250th anniversary of the United States, some of Cambridge's leading experts on US history share their thoughts on the declaration that forged a nation.

The United States declared its independence from Britain 250 years ago. Here's how the US's relations with other nations — and its global image — have changed since.