"It is a federal offense … to offer any man a federal job in return for a favor."

This is one of those things which is altogether normal and fairly humdrum when done properly and discreetly, with careful choice of wording. "You drop out of the race for President now, and I'll make you Secretary of State or something similar." It's well known that a hefty campaign contribution substantially increases your odds of being made an ambassador to some country or other. If done properly, not couched in explicit "if... then..." statements, then no laws have been broken, and it's more or less politics as usual. And it's entirely appropriate. Assume the best case scenario, where you've got (to pick an example that may or may not bear any resemblance to actual events) the Hillary wing of the Democratic Party and the Barack wing. The Barack wing is in the ascendancy and almost has everything locked up. But the Hillary wing is legitimately concerned about the impact a Barack primary victory will have on American foreign policy; it's important to show foreign countries that we're not as divided as they (and we) sometimes think we are, and the Hillary wing is more hawkish in general than the Barack wing. So the Hillary wing, knowing it is facing defeat, but still has power to make things either harder or easier for the Barack wing's success, extracts policy concessions, to ensure that its foreign policy concerns are taken seriously. One of the policy concessions is naming one of the Hillary wing's people as Secretary of State, to insure that its views on foreign policy will be heard at the highest levels. All not only appropriate but an essential part of democracy.

But then there's the sleazy, Rod Blagojevich style of deal-making, where you simply buy people off with purely patronage positions. These deals are motivated by pure, personality-driven power politics rather than any principled concerns.

Legally, the precise language of various conversations will be important (as they will be in Gov. Blagojevich's trial). If all that was promised was that the White House would "look into" hiring him for some position or other, then probably ok. If they were STUPID and discussed a quid pro quo explicitly, then goodbye and sayonara, hope you look good in a jumpsuit. Sestak himself needs to be careful with his comments; I would advice him to not be quite as precise with his comments as he has been. A WH official saying "look, there's still some good vacancies here, we really need you to come help out the administration" would, in context, be clear as a job offer to somebody in Sestak's position, but would also be legally acceptable, as it is not an explicit quid pro quo. But Sestak was asked: "Is it true that you were offered a high ranking job in the administration in a bid to get you to drop out of the primary against Arlen Specter?" And he answered "yes." It's entirely possible that the offer wasn't that direct, however clear it may have been to Sestak. He risks either slandering somebody who didn't actually commit a crime or, if a crime was committed, getting himself in trouble for, at best, misprision of a felony, for failing to report the offer to the proper authorities.

Not sure there is anything to see here. If this is illegal then probably about a quarter of high level political appointments in the last 50 years are illegal. It is all sausage making and much ado about nothing. Unless money or other considerations occurred, I don't consider this to even be unethical.