After a stretch in which an endorsement from Sarah Palin was considered a rarity, the former Alaska governor has become something of an endorsement machine as of late. In the past week alone, she has endorsed four candidates, ranging from a tea party contender for Senate in her home state of Alaska to the GOP establishment favorite for Iowa governor. Palin has backed both clear winners and decided long-shots; she's weighed in on behalf of "mama grizzlies," but an extra X chromosome doesn't necessarily mean an automatic endorsement (see Hutchison, Kay Bailey). Some candidates (such as former Redskins tight end...