DOYLESTOWN — Canvassers and party loyalists came out to a parking lot, hockey rink and banquet hall on Sunday to see Pennsylvania's U.S. Senate candidates as they vie for support in Philadelphia's heavily populated suburbs packed with moderate, swing voters.

Philadelphia's four suburban counties, home to one in five Pennsylvania voters, are the focus of much attention from U.S. Rep. Joe Sestak, a Democrat, and former Congressman Pat Toomey, a Republican, in the final days of the campaign.

Registration among the 1.7 million voters in the four "collar" counties — Bucks, Chester, Delaware and Montgomery — is nearly balanced between Democrats and Republicans.

Sestak, wearing a green jacket with an emblem from the aircraft battle group he commanded in his Navy career, hit populist notes to fire up a few dozen canvassers in a Doylestown parking lot, targeting what he characterizes as Toomey's corporate favoritism.

"Just make sure everyone comes out for us, for the people — we the people, not the corporations," he said.

Sestak was introduced by U.S. Rep. Patrick Murphy — an Iraq war vet who himself is in a tight contest to win a third term — and many of the lawn signs peppering the area play up their military service: "We're voting for the paratrooper and the admiral."

In another part of Bucks County, Toomey spoke to more than 200 people in a Bristol banquet hall, before heading to a Delaware County ice rink on the other side of Philadelphia in Sestak's congressional district.

"The southeast is a swing area, where voters — you know how this goes, it's every election cycle — voters in some cycles they'll vote for Democrats, other times they'll vote for Republicans," Toomey told a seated crowd of about 150.

Toomey has ridden a wave of voter dissatisfaction over joblessness and the policies of President Barack Obama, including the new federal health care law.

Along with turnout in heavily Democratic Philadelphia, the campaigns will closely watch the tally in the suburbs, where Democratic registration has increased in recent years.

Toomey and Sestak are competing to succeed five-term Sen. Arlen Specter, whom Sestak beat in the May primary. Beginning in 2000, no candidate in a general election race for president, U.S. senator or governor has lost the four suburban counties, but won the election.

Pollsters characterize the counties' voters as fiscally conservative, but liberal to moderate on abortion rights and environmental causes.