They wanted to defend America first and foremost Isolationists thought America should not intervene in foreign affairs and should be focused on domestic issues to improve American people's lives. Their doctrine can be summed up by Lindbergh's motto "America First". It was demonized during the Cold War and eventually took a negative connotation associated with xenophobia. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.