BRUNSWICK — We are living in interesting times. Some might even say “desperate.” I’m speaking mainly about the presidency of Donald Trump. In Maine, we must also contend with a governor named Paul LePage. Then there’s this. On Jan. 21, 2017, the day after Mr. Trump was inaugurated as our 45th president, my 33-year-old son, Mark Baumer, was hit and killed while walking across America to raise awareness about climate change.