No longer willing to say "no" outright, Barack Obama tells Tim Russert running for the presidency is now a "possibility," one he'll give further thought to after next month's elections. The drumbeat -- he's taken over the Times Op-Ed page: like David Brooks earlier in the week, Maureen Dowd gave him yesterday's column (sub. req'd); Frank Rich followed suit today -- has apparently had an impact. (The video clip only works on Windows machines running IE; those using other platforms may have better luck with the entire interview. Discussion of POTUS possibilities occurs around minute 25.) [ETA: Bob Herbert chimed in on Monday. Naturally.]