Complex sentence: Wabanaki soldiers from Canada are still permitted, due to this treaty, to join the US military, and have done so in the recent conflicts the US has engaged in, including the Afghanistan war and the Iraq War.
Split into simpler sentences: Wabanaki soldiers from Canada are still permitted, due to this treaty, to join the US military. They have done so in 21st-century conflicts the US has engaged in, including the Afghanistan war and the Iraq War.