No, the chief main reason for US entry into WWII was still Pearl Harbor. When USA declared war on Japan, Germany also declared war on the US. And the reasons why Japan bombed US were many, but main reason was because US embargoed Japan over their invasion of China. And Japan thought they needed to defeat USA if they wanted to safely control the resources of the Pacific
As for WWI, its actually a bit complicated than that. But its mainly the result of British propaganda (very excellent play by play, mind you) and Germany's unrestricted submarine warfare making US anxious. Then the Zimmerman thing happened...