Buffet upgrades America to "Buy"

In an NYT op-ed by the Oracle of Omaha, he shows leadership in this difficult economic time in urging readers to accumulate stocks instead of sitting on cash, providing some historical insight:

Over the long term, the stock market news will be good. In the 20th century, the United States endured two world wars and other traumatic and expensive military conflicts; the Depression; a dozen or so recessions and financial panics; oil shocks; a flu epidemic; and the resignation of a disgraced president. Yet the Dow rose from 66 to 11,497.

And guess what? The Dow is up (so far). Would his article have something to do with it?