In the latest update of the
Poll of Polls, Kerry has returned to a statistically significant lead (allbeit before any 'Reagan bounce'), and the Nader effect continues to shrink: in the last 23 polls (since late April), Nader has cost Kerry 2% or less.
The Nader effect is shrinking because the share of vote he is taking from Kerry is down from 3.1% in March to 2.3% in May and 2.1% in June (June result only includes 7 polls). At the same time Nader is taking more and more votes from 'don't know, other, won't vote, etc.' and continues to draw 1% from Bush.