In what could prove the most enlightening window yet into the personality and politics of the famously opaque Supreme Court nominee Elena Kagan, the Clinton Presidential Library last week released 75,000 emails sent to and from Kagan in the late 1990s, when she was a domestic policy adviser for Bill Clinton. Senators will be delving into Kagan's past when her confirmation hearing starts on June 28. Thanks to the emails and the media's compulsion to scrutinize them, here are five things we already know about her:   

1. Kagan is no stranger to foul language: Kagan occasionally peppered her emails "with salty language that would make Vice President Joe Biden proud," says Josh Gerstein at Politico. In one message, she used "a New Yorkerized version of the word 'unbelievable'" — un(expletive)believable — to respond to a message about a legislative glitch involving welfare reform.

2. She can be sarcastic: Kagan once "chastised an underling," says Amy Goldstein in The Washington Post, for informing senior White House advisers that Kagan's office would be releasing a "policy announcement of sorts." "'Of sorts?'" Kagan emailed. "Not quite the attitude we want to convey." Critiquing another colleague's email, she replied: "Not to carp, but on memos to the president, it's usually wise to spellcheck."

3. She was a big fan of Bill Clinton: The New York Times notes that in several of the emails Kagan is "fiercely protective" of then-president Bill Clinton, demanding that her staff take extra care to avoid making him look bad and, at one point, marvelling at his power of recall in a note with the subject line, "Elephantine": "Look at today’s AP story re the president’s comments on hiring welfare recipients... Absolutely amazing the way he remembers things."

4. Kagan isn't afraid to speak her mind: Kagan frequently wrote tough, sometimes caustic emails to her colleagues, even if her views were unpopular in the administration. In one message, she clashed with speechwriters over a line in an advance draft of Clinton's 1997 State of the Union address. The line included a quote from the Biblical prophet Isaiah about being a "repairer of the breach" — a reference to Clinton's desire for bipartisanship. "That quote from Isaiah is the most preposterously presumptuous line I have ever seen," Kagan wrote. "The president would deserve it if the press really came down on him for this." The quote stayed in.

5. Kagan was enthusiastic about affirmative action: The emails will give Republican senators looking for evidence of Kagan's leftward slant fresh ammunition, says Roger Clegg in National Review. In one message she noted that presidential race adviser Chris Edley was leaving and lobbied to be put in charge of affirmative action in his place. "I know the issue well (because I teach it) and care about it a lot."