MARK WARNER'S CALCULUS. Former Virginia Gov. Mark Warner, who considered a 2008 presidential race but then said the strain would be too much for his family, has announced he will run for the Senate seat of retiring Republican John Warner. The Democratic cell phone entrepreneur with a reputation for technocratic competency has been endlessly buzzed about as a potential Hillary Clinton running mate, mostly due to his ability to woo centrist voters in newly purple-ish Virginia. Will the Senate race be Warner's last stop on the road to November 2008, or would he still consider a V.P. bid? --Dana Goldstein
