This first link is the first speech Woodrow Wilson used when discussing the war in Europe with the Congress. The second website is the page where this speech as well as some opposing speeches regarding Wilson's talking points can be found. For instance, if the first document was used it discusses the U.S. desire to remain natural, to let Europe handle its own fairs, though Wilson acknowledges the U.S. may play a role in this. Opposing views argue for a stronger stance of isolationism. This could be an interesting way for students to see the two sides, though the wording is a bit older fashioned.
This next source is a secondary source that reads more like a chapter overview, though it puts a lot of information into perspective. It is also fairly short and may serve as a quick reminder to Isolationism, though it is more tailored to the 1930s and I was unsure as to what years you wanted to talk about.
The website loaded on my phone, though when I check it when I got home a pop-up shows up. I refreshed the page and it disappeared, not sure if it will open for you but I am included in this source just in case. The source contains a full lesson plan pertaining to the two topics in a WWII context. There are multiple primary sources to choose from (if the pages lets you see them) and I thought the inclusion of how the sources were used might be useful.
The final source is the one I found pretty interesting, while it is lengthy and primarily a secondary source, it references quotes and language used within primary sources. I would think focusing in on the wording used would be an interesting way for students to make sense of the tone and feelings of the time. Of course, some things may need to be cut out if it were used as a handout.
Anyways, I hope some or one of these links is useful. Sincerely, Tyler Cannon.