What was the major cause of indian-white conflict during the late 1700s and early 1800s?

White expansion. War between Indians and the whites was very common because the whites seemingly had quite an appetite for the Indian land. Indians struggle to contain this  aggressive  expansion led to war with hope to reduce American settlement and expansion.

they united the colonies in their fight against the british.

when world war i broke out across europe in 1914, president woodrow wilson proclaimed the united states would remain neutral, and many americans supported this policy of nonintervention. however, public opinion about neutrality started to change after the sinking of the british ocean liner lusitania by a german u-boat in 1915; almost 2,000 people perished, including 128 americans. along with news of the zimmerman telegram threatening an alliance between germany and mexico, wilson asked congress for a declaration of war against germany. the u.s. officially entered the conflict on april 6, 1917.