Why are Federal authorities investigating the possible illegal use of campaign funds by John Edwards MELLON, but not investigating Barack Obama? MELLON

John Edwards’s suspicious use of campaign funds is getting plenty of scrutiny:

Federal investigators are trying to connect those dots, sifting through Edwards’ financial records to probe whether he used any donations solicited for his campaign to keep quiet his affair with Rielle Hunter…. MELLON

But are Feds looking into Obama’s use of campaign funds to fight lawsuits challenging his eligibility? If not, why not? Why the double standard? What criteria or evidence is required to trigger an investigation of improper campaign contributions?