On the first question, it looks like CQ's Jeff Stein, who broke the original story earlier this week, has cleared things up. He told an interviewer yesterday that, according to sources, Harman's potential crime was "to do a favor in exchange for something of value, which is to say, to get appointed to be the chair of the House intelligence committee."
In other words, a violation of the federal bribery statute, Title 18, Section 201. By the terms of this law, it doesn't matter whether Harman followed through on her pledge to take action on the AIPAC case -- only that she said she would, in exchange for something of value.
But would the statute apply to what we know about the Harman case?
Experts on bribery laws say there are two major sticking points. The first is whether the action that Harman reportedly pledged to take -- urging the White House to ease up on prosecuting the AIPAC lobbyists Steve Rosen and Ken Weissman -- was done as part of Harman's official duties, as the law requires.
A narrow reading of the law would suggest that weighing in with the Republican White House on a criminal case involving classified material is not traditionally part of the duties of a Democratic congresswoman, even one on the Intelligence committee. But Peter Henning, an expert on white collar crime at Wayne State University Law School, says courts have construed "official duties" more broadly. For instance, in 1988, the New York congressman Mario Biaggi was charged with bribery in connection to writing letters to New York City officials, urging them to favor a local business. Biaggi argued in his defense that the letters hadn't been written in his official capacity as a member of Congress. But the court rejected that argument, with the judge essentially declaring, as Henning put it, "that's what members of Congress do!"
The second potential sticking point could be more significant. According to Tara Malloy of the Campaign Legal Center, a good government group, the public official merely needs to believe that the thing he or she hopes to receive is of value. That thing need not be financial, or even tangible. But Henning said it's still unclear whether help in getting the Intelligence committee chairmanship would qualify, since there's no well-known precedent in which the thing of value has been a congressional committee leadership post, as in this case. "It's certainly a gray area," he said.
Both Malloy and Henning said it wasn't unreasonable for DOJ lawyers -- hearing the wiretapped conversation between Harman and the suspected Israeli agent, in which a quid pro quo appeared to have been agreed to -- to conclude that the issue deserved further investigation. But whether the department would have been able to build a solid case against Harman -- even had Gonzales not reportedly stepped in to shut it down -- remains a very open question based on the available evidence.