The critical operations were purely naval.

In the first of these, Commodore Dewey's squadron destroyed the entire Far Eastern squadron of the Spanish in Manila Bay; in the second, Admiral Sampson's squadron destroyed the entire Atlantic squadron of the Spanish near Santiago de Cuba.

The two naval victories compelled Spain to make terms of peace practically as the United States wished.
Attention is invited to the fact that this war was not a war of conquest, was not a war of aggression, was not a war of invasion, was not a war carried on by either side for any base purpose; but was in its intention and its results for the benefit of mankind.
The Russo-Japanese War was due to conflicting national policies.
While each side accused the other of selfish ends, it is not apparent to a disinterested observer that either was unduly selfish in its policy, or was doing more than every country ought to advance the interests and promote the welfare of its people.

Russia naturally had a great deal of interest in Manchuria, and felt that she had a right to expand through the uncivilized regions of Manchuria, especially since she needed a satisfactory outlet to the sea.

In other words, the interests of Russia were in the line of its expanding to the eastward.