I really liked this movie but I think most will either not understand the significance or be too biased politically to just enjoy it for what it is.
I do think one should know a little bit about Ted Kennedy and the car accident that derailed his possible goals of running for President. Again, let go of any prejudices you might have.
If you can get by all of that, spend 10 minutes googling the actual situation (not the movie, don’t want to spoil it), I think you can enjoy this movie as I did and the very republican, conservative friend of mine that saw it with me.