WON'T GO THERE  —  In the thick of a campaign it is easy to overrate the importance of an endorsement or a political hit.  But it is difficult to overstate the significance of John Lewis' switch from the Clinton to Obama camps because it is a devastating blow on two or three levels wrapped together in a single person.

Clinton Camp May Regret Largely Turning Its Back on Caucus States  —  Among the costliest decisions Hillary Rodham Clinton's presidential campaign has made this year was to largely cede caucus states to Barack Obama.  It is one that, in retrospect, baffles Democratic strategists and, even more so, the operatives on Obama's team.

HALPERIN'S TAKE: Why a John Lewis' Defection Would Be Such a Big Deal  —  Lewis is a universally respected, historic figure who is the first prominent Democrat to go from squarely in Clinton's camp to Obama's.  The rationale he seemed to give to the New York Times strikes at the heart …

McCain-Obama Race Could Redraw Electoral Map  —  Black Turnout Might Put South in Play;  —  New Math in West  —  In recent presidential elections, the electoral map largely has been fixed, with certain regions predictably loyal to one party or another and the competition narrowed to fewer than 20 battleground states.