It's pretty simple.

The mainstream media is interested in news, i.e., what's new, or, a la Slate.com, what's contrary to what we currently believe.

The GOP, particularly since the ascension of Karl Rove, has no scruples in discrediting its opponents.

So the GOP presents contrary images of Democrats, over which the mainstream media has a feeding frenzy.

Pres. Obama is somehow involved in a war on women, John Kerry's decorated Vietnam War record is suspect, Al Gore makes huge mistakes. Al Gore's mistakes are actually tiny, George W. Bush's are huge, but we all know Bush isn't that smart so that's not news. But Gore: He should know better. 

Democrats attack Republicans for what they are, which isn't news. Republicans attack Democrats for what they are not, which is. It's the only way the GOP, with its platform (supporting the rich few against the many), can thrive.

Indeed, the GOP attacks Dems for what it, the GOP, is actually guilty of: being anti-women, avoiding service, fudging economic numbers. As I've stated elsewhere, this is the ultimate in propaganda.

Expect more.

Supporting the troops: In the 2004 election, the record of John Kerry, who served in Vietnam, was questioned, while George W. Bush, who sat out the war in Texas and Alabama, mostly received a bye.