How often does MSM ignore a major Democrat speech?

Almost never - unless the Democrat in question is Joe Lieberman. Weekly Standard's William Kristol:

If a senator gives a speech, and no major newspaper reports it, does it matter? Joe Lieberman spoke in Washington Thursday on "the politics of national security." The next day, the New York Times, the Washington Post, the Wall Street Journal, and USA Today ignored his talk. Most Democrats will ignore it.

The End Zone provides news the MSM will not! Joe Lieberman, Thursday, making a speech which was solid gold:

Iraq has become the singular litmus test for Democratic candidates. No Democratic presidential primary candidate today speaks of America's moral or strategic responsibility to stand with the Iraqi people against the totalitarian forces of radical Islam
[...]
Even as evidence has mounted that General Petraeus' new counterinsurgency strategy is succeeding, Democrats have remained emotionally invested in a narrative of defeat and retreat in Iraq, reluctant to acknowledge the progress we are now achieving. . . .
[...]
[T]here is something profoundly wrong--something that should trouble all of us--when we have elected Democratic officials who seem more worried about how the Bush administration might respond to Iran's murder of our troops, than about the fact that Iran is murdering our troops.

There is likewise something profoundly wrong when we see candidates who are willing to pander to this politically paranoid, hyper-partisan sentiment in the Democratic base--even if it sends a message of weakness and division to the Iranian regime.

For me, this episode reinforces how far the Democratic Party of 2007 has strayed.