Aside from a brief surge in support following his mid-May primary victory over incumbent Senator Arlen Specter, Sestak's support has fallen in a narrow 36% to 40% range since tracking began in February.

Last month, Toomey led Sestak 45% to 39%.

When leaners are included in the totals, Toomey's lead slips one point. With the leaners, 48% favor Toomey and 40% Sestak.