Comedy actor and screenwriter Seth Rogen is like a conservative caricature of an Obama supporter. He’s from Canada, where “communism is not a terrible word,” and plays a pothead in the movies. As it turns out, he’s not a regular donor at all. Rogen’s max contribution to Democrats in 2009 is his only one on record. But as President Obama lays the groundwork for his $1 billion reelection campaign, Rogen’s is a fresh checkbook to tap.