WASHINGTON -- A second poll in as many days showed a dramatically tightening contest in Pennsylvania's Democratic U.S. Senate primary, with Joe Sestak holding a narrow lead over Katie McGinty, according to a Franklin & Marshall poll released Thursday.
The survey found Sestak up 33-27 just days ahead of the April 26 primary. In March the same poll found Sestak leading McGinty by 17 percentage points -- but that was before McGinty allies poured more than $4 million into promoting her and attacking the front-runner.
The Franklin & Marshall finding comes a day after a Monmouth University poll found Sestak and McGinty in a dead heat.
While the new survey showed Sestak with a lead, there were so many undecided voters in the Senate race -- 29 percent -- that "the outcome remains unpredictable," according to  a Franklin & Marshall summary.
Among likely Democratic voters Sestak led 38-29, but with many of those voters also undecided.
Sestak, a former admiral and congressman from Delaware County, and McGinty, Gov. Wolf's former chief-of-staff, are the two leading candidates competing for the nomination to challenge Sen. Pat Toomey (R., Pa.). The race against Toomey is expected to be one of the most critical in the country.
Braddock Mayor John Fetterman registered 8 percent support in the Democratic primary. Western Pennsylvania candidate Joseph Vodvarka -- who was just restored to the ballot this week after initially being disqualified -- was not included in the poll.
Democrats inside Pennsylvania for weeks have said Sestak had the lead, but that an ad barrage from McGinty and her Washington supporters -- including the Senate Democratic campaign arm -- was closing the gap.
Key questions have centered on whether the push arrived too late, and how the presidential campaign will affect the Senate race's final stretch. Now that the New York primary is over, presidential candidates are turning their attention to Pennsylvania, potentially drowning out the Senate candidates, but also drawing out more voters.

The poll was conducted April 11 to 18 and surveyed 510 Democrats. The margin of error was 4.2 percentage points. 

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