The Judicial branch can check the power of the Executive branch by 1.ruling its acts unconstitutional.
2.not ratifying its treaties.
3.impeaching the President.
4.overriding the President's veto

1.ruling its acts unconstitutional.

Explanation:

Judicial branch may check both the legislative and executive by declaring laws unconstitutional. Obviously, this is not the whole system, but it is the main idea.

b. sec, foreign relations

roosevelt believed that in light of the country's recent military successes, it was unnecessary to use force to achieve foreign policy goals, so long as the military could threaten force. this belief, and his strategy of “speaking softly and carrying a big stick,” shaped much of roosevelt's foreign policy.