Dan Froomkin’s indispensible White House Briefing column:

Steven Thomma of Knight Ridder Newspapers reports that shock jock Howard Stern’s on-air crusade to defeat President Bush is having an impact.

“Nationwide, 17 percent of likely voters listen to Stern’s radio show, according to the poll released Thursday by the New Democrat Network, a Washington-based group. They favor Kerry over Bush by 53 percent to 43 percent, and by 59 to 37 percent in 18 battleground states.”

The group’s poll memo notes that “four percent of likely voters this fall are swing voters who listen to Howard Stern, showing Stern’s potential ability to impact the race.”