Suppose congress tried to create new laws that violate the constitution. could the president and/or the supreme court block
congress's actions? if so, how?

Of course he can. If a president has a doubt about the constitutionality of a piece of legislation, he can order his official to go to courts and file a case. In the ultimate end, the US Supreme Court will rule on the case.

Explanation:

lee and grant, both of whom held the highest rank in their respective armies, had known each other slightly during the mexican-american war (1846-48) and began their dialogue by exchanging awkward personal inquiries. characteristically, grant had arrived in his mud-splattered field uniform while lee had turned out in full dress attire, complete with sash and sword.

explanation: