While the Republicans still have the potential to make larger gains in November, with less than 100 days to go the chances are greater that there will be a modest GOP increase of four to six seats in the U.S. House. Democrats are currently leading in 255 Congressional races, while Republicans are ahead in 161 and another nineteen are "toss ups,'' according to a newly completed survey of the 435 races nationally by the National Political Review.

Although there have been a number of changes in the status of individual races, the net results are identical to those in our last survey conducted in late April. Currently the Democrats hold 268 seats, compared to the Republicans' 166, with one open seat, formerly held by the late Cong. Edwin Forsythe (R-N.J.), who died in March.

Of the nineteen ''toss up" races, fourteen are currently held by Democrats and five are held by Republicans, giving the GOP greater opportunities for gains. In the fourteen Democratic seats rated as toss ups, nine of the incumbents are seeking re-election and the five remaining are

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