What sets Drudge apart as much as anything is its ability to attract well-placed leaks and traffic in the freshest and rawest material — though sometimes including what some have considered smears.

On the Republican side, a generation of campaign consultants has grown up learning to play in Mr. Drudge’s influential but rarefied world. They have spent years studying his tastes and moods while carefully building close relationships with him that are now benefiting some Republican presidential campaigns — and that others are scrambling to match.

The early advantage on their side, in the view of several Republicans, seems to have gone to Mitt Romney, who hired the former Bush political aide who had been the central party’s prime point of contact with Mr. Drudge, Matthew Rhoades. His status was solidified after the 2004 election at a steakhouse dinner in Miami with Mr. Drudge, who for all his renown in politics is a somewhat spectral presence who rarely agrees to meet with political operatives or journalists and who did not respond to requests for an interview for this article.

So important was the Romney camp’s perceived advantage in the eyes of aides to Senator John McCain, Republican of Arizona, that at one point this year they even considered sending an emissary to Miami to build their own relationship with him, two former McCain campaign officials said. (Mr. Drudge ignored the invitation, one of the officials said.)

But, typical of a campaign with a reputation for exploiting every advantage and trying to neutralize every disadvantage, Mrs. Clinton’s communications team, led by Howard Wolfson, is not leaving Mr. Drudge to the Republicans. Five current and former Democratic officials said Mrs. Clinton has on her side the closest thing her party has ever had to Mr. Rhoades in Tracy Sefl, a former Democratic National Committee official, who has established a friendly working relationship with Mr. Drudge — and through whom Mrs. Clinton’s campaign often worked quietly to open a line of communication.

Image Matt Drudges site made a mark when another Clinton dominated political news. Credit... Evan Agostini/Getty Images

That effort has helped to mix some positive stories in with the negative fare about Mrs. Clinton that Mr. Drudge still serves up regularly, they said, though Ms. Sefl’s fingerprints are usually impossible to spot.