When Barack Obama confronted Hillary Clinton's vote on Lieberman-Kyl, the Clinton campaign quickly mailed a detailed explanation of her vote to Iowans.

When Barack Obama told the New York Times that he would start to challenge Clinton more aggressively and picked her refusal to detail her Social Security fix as his first target, within 10 hours the Clinton campaign was on the air in New Hampshire with an ad attempting to inoculate any perceived vulnerabilities on Social Security.

Depending on the size of the buy, more New Hampshire residents probably saw the Clinton ad before they heard too much about Obama's charge on Social Security. And notice how Clinton frames her opposition: by using George W. Bush as a foil.

The tag line is an encapsulation of Clinton's appeal to Democrats:

"These days, it seems like every candidate on earth is coming here for You.
But which candidate has been there for you all along?"

It's also the first time a Clinton ad has even acknowledged the presence of other candidates.