Fitzgerald ratcheted up the investigation around February, 2004. This is when Rove and Libby first went to the grand jury and either failed to disclose or lied about how they learned of Valerie Plame Wilson. It's also when Rove failed to disclose the now notorious e-mail with Hadley.

I'll let Greg take it from here, but you really must read his whole article, and then re-read Murray:

Thanks to Waas, for the first time, we may now know for a fact that Rove and other Bush advisers viewed the truth about the run-up to war as something that could destroy his re-election prospects. It is entirely plausible that Bush advisers calculated that if it came out that they'd outed Plame, Congress would have been forced by the resulting firestorm to run a far more aggressive investigation of Bush's pre-war deceptions - and possibly uncover the smoking gun Waas reports on, among other things. Remember, Libby and Rove testified in early 2004, during the heat of a presidential campaign which Rove himself had apparently concluded was at risk if existing hard evidence of Bush's deceptions surfaced.

So it seems plausible that Libby and Rove sought to minimize the chance of the aggressive congressional oversight that might have resulted if it became known that they'd outed Plame. In short, misleading the grand jury about Plame may simply have been a key piece of a broader effort to get past the election before the truth about the run-up to the war surfaced to sink his campaign.

Sargent explains it again:

White House officials, including Bush himself, withheld critical information it had about doubts over supposed evidence of Saddam's nuke ambitions in order to better make the case for war. Then they subsequently discovered that hard evidence existed of that duplicity. Then, anxious that this evidence might surface before the 2004 reelection, they engaged in a relentless campaign to cover up what really happened during the Iraq run-up and to prevent an aggressive congressional investigation until after the election. They relied on Pat Roberts to run a pseudo-investigation; they withheld the daily briefs; they leaned on Hill allies not to talk to the press. And they obscured their role in the outing of Plame to prevent an outcry that would have certainly forced Congress and the press to probe far more aggressively than they did. And they succeeded: If Congress and the press had been more aggressive -- and this may be the real significance of Waas's story -- it's perfectly possible that John Kerry would now be president.

This is giant news, and Congress and the MSM need to get on it. We can't expect Fitzgerald to do everything himself.