Hillary ClintonHillary Rodham ClintonRoger Daltrey: 'Dead dog' would have beaten Clinton Clinton targets Trump in speech, urging supporters to 'resist, insist, persist, enlist' Clinton defends April Ryan, Rep. Maxine Waters in speech MORE has a huge lead over Bernie SandersBernie SandersIn California race, social justice wing of Democrats finally comes of age Sanders to headline progressive 'People's Summit' The Hill's 12:30 Report MORE in Pennsylvania just three weeks before the primary there.
A Harper Polling survey released Tuesday found Clinton taking 55 percent over Sanders at 33 percent, with 12 percent undecided.
Clinton’s lead is down from the same survey in March, when she had a 30-point lead.
In the race to be the Democratic nominee to challenge incumbent Sen. Pat Toomey (R-Pa.), former Rep. Joe Sestak (D-Pa.) is in the lead with 41 percent support, following by former gubernatorial chief of staff Katie McGinty (D) at 31 percent.
McGinty has the support of the Democratic establishment, but continues to run behind Sestak in fundraising and in the polls.
Sestak narrowly lost to Toomey in 2010, a huge year for Republicans.
The Harper Polling survey of 603 likely Democratic voters in Pennsylvania was conducted between April 2-3 and has a 4-point margin of error.