Maybe with the amounts so far, but his MO is to 'take positions' so large they change the fundamentals.
A timely comment. Just today Bob Novak has an article on Townhall about Soros's doubts about Dean. (my italics)
Soros Doubts
Robert Novak
WASHINGTON -- Left-wing billionaire investor George Soros, who appeared to support Howard Dean for president, now is privately expressing doubts about the Democratic Party's front-runner.
In conversations with political friends, Soros confided he has become alarmed by Dean's recent performance and wonders whether the former Vermont governor is capable of defeating George W. Bush. In one such chat, Soros suggested he is interested in retired Gen. Wesley Clark.
Soros has made clear his visceral opposition to President Bush and his passionate desire to find somebody who can defeat him for a second term. The financier has pledged $10 million to America Coming Together (ACT) and $2.5 million to MoveOn.org -- both anti-Bush organizations.