What were the consequences of US imperialism in places like the Philippines and China?
You could argue that one of the consequences of US imperialism in these areas was World War II.
When the US took the Philippines and made inroads into China, it placed itself in an area that was already of great interest to Japan. Japan felt that it, too, should be an imperial power and it felt that its Asian "neighborhood" was the perfect place to take such an empire. If the US had not had interests in China and possession of the Philippines, Japanese expansion would not have been such a big deal. However, Japanese expansion was sure to run up against US interests because of the US's imperial possessions.
Because the US had imperial possessions in an area that Japan coveted, Japan felt the need to attack the US at Pearl Harbor to prevent the US from resisting Japanese expansion. Seen in this light, US involvement in WWII was a consequence of US imperialism in this area.