The long training runs are in the rearview mirror, and this weekend, the 30,000 athletes taking on the 129th Boston Marathon will go to bed dreaming of personal bests — or just making it across the finish line. Of course, the Boston Marathon is much more than a footrace. It is a rare opportunity to set aside our political differences, to ignore municipal borders, and for one day, to come together as neighbors in a joyful celebration of perseverance, personal achievement, and civic pride.