"Minor" political events that had a big impact in shaping your outlook

[Fuzzy Bear Loves Christian Missionaries]

Kate Steinle's death, and the surrounding circumstances of the person responsible being in the country due to "Sanctuary Cities".  This reframed my views on immigration.  The immigration issue to me is not primarily one of what policy ought to be (on which I am flexible).  Ms. Steinle's death, and the circumstances around it caused me to see that the issue is one of people refusing to enforce existing laws that have been legitimately enacted, and have never been legitmately repealed.