Why Joe Biden might be taking it easy on Pete Buttigieg

The most famous unspoken Democratic presidential candidate alliance is probably the one between Sens. Bernie Sanders (I-Vt.) and Elizabeth Warren (D-Mass.). But there might be one brewing between former Vice President Joe Biden and South Bend, Indiana, Mayor Pete Buttigieg, as well -- at least on Biden's end.Biden and Buttigieg aren't old friends like Warren and Sanders, but there are some logical strategic reasons for why that might be the case. Biden hasn't really gone after the 37-year-old ma