In general election matchups, Obama leads McCain by 51-44 percent, similar to the last two ABC News/Washington Post polls. Standings in a Clinton vs. McCain race are 49-46 percent, again roughly similar to previous ABC News/Washington Post results.
About a quarter of Clinton supporters (26 percent) say they'd favor John McCain over Obama, and about as many Obama supporters (22 percent) say they'd take McCain over Clinton. However that's a measure taken in the heat of Democratic battle; again, how the race ends, and goes forward toward November, likely will count for much.
http://abcnews.go.com/PollingUnit/Vote2008/Story?id=4837828&page=2