Apparently Justice Kagan was actually involved in Obamacare discussions while at DOJ

From Fox News:

With just weeks until the U.S. Supreme Court considers the constitutionality of President Obama's health care law, there are new calls for Justice Elena Kagan to recuse herself from the case.
Her critics point to a 2010 case regarding a San Francisco health measure, in which then-Solicitor General Kagan's office filed an amicus brief touting the newly passed health care law.
In May 2010, after Kagan had been nominated to the nation's highest court, Principal Deputy Solicitor General Neal Katyal sent her a memo outlining the cases in which she had "substantially participated." Kaytal specifically referenced the Golden Gate case, noting that it had been "discussed with Elena several times."
That's enough to convince Heritage Foundation Senior Legal Fellow Hans von Spakovsky that Kagan shouldn't take part in the current health care case before the high court.
"I don't see how any ethical lawyer adhering to professional codes of conduct could not consider that they need to recuse themselves from this case," he said. . . .