"He strikes me as a super-successful graduate student: the brightest, quickest, most articulate guy in the seminar. In his career, he has advanced mainly by talking and writing -- not doing -- and may harbor a delusion common to the well-educated: that he can argue and explain his way around any problem."That's Washington Post economics columnist Robert Samuelson sizing up Barack Obama. Maybe too dismissive, but it zeroes in on the Democratic presidential candidate's main weakness. I worry about the "not doing." In my first posting, I said Obama missed a perfect opportunity to do something about the crisis in his Trinity United Christian Church congregation. Instead, he talked, and talked, and talked some more. When all the talking didn't accomplish anything, he quit the church where he'd worshipped for 20 years. Well, I guess he finally did do something.