NEW YORK - Pennsylvania's simmering race for U.S. Senate came to Manhattan over the weekend.

But even with three of the four candidates on hand for the annual Pennsylvania Society gathering, the weekend's big headliner - Donald Trump - cast a shadow.

Among many commonwealth Republicans, there was an undercurrent of concern that if Trump leads their presidential ticket next year, he could devastate GOP Sen. Pat Toomey's chances of winning a reelection fight that could help decide control of the Senate.

"There's a lot of concern that [with] Donald Trump, and one or two other candidates, that there will be a down-ballot drag. It's certainly going to affect Senate candidates more than anyone else," said Rep. Charlie Dent, an Allentown Republican. "Pat Toomey has done a terrific job as a senator and has positioned himself extraordinarily well to win reelection - but he can only control what he controls. They don't control the national environment."

He and other Republicans worried that Toomey, who presents himself as a reasonable, constructive conservative, could be tied to the divisive GOP front-runner if Trump wins the party's nomination and sets the tone in the 2016 presidential race.

Trump's rise and potential impact was the dominant topic at a Friday briefing hosted by GOP consulting firm Quantum Communications.

"The thing I worry about is, are we going to hold the Senate?" said Ed Rollins, a longtime national Republican consultant. "The Senate is a real testing ground this time."

Toomey, however, dismissed the concerns after skipping Trump's Friday speech at a state party fund-raiser.

"It's very unlikely that Donald Trump will be on the ballot that I'm on," Toomey said, doubting that the billionaire will win the nomination. He noted that early front-runners rarely go on to capture the GOP nod.

Toomey didn't say who he was backing in the race - "I don't have anything for you on that one" - but stressed his team would "run our own race."

This weekend that meant a fund-raiser, bouncing among events, and speaking out against the international nuclear deal with Iran (which his Democratic rivals support) at a talk hosted by the Pennsylvania Manufacturers' Association.

Two of the Democrats who have lined up to challenge Toomey made the trip to New York; a third, Joe Sestak, handed out blankets, school supplies, and canned food to the needy in Harrisburg.

Toomey crossed paths with one potential rival, Braddock Mayor John Fetterman, at the Waldorf Astoria, the hub of the weekend's politicking.

They posed for a photo in front of a Republican cameraman following Fetterman.

The mayor - 6-foot-8, tattooed, and wearing jeans and a black work shirt - made the posh Waldorf lobby his unofficial home for much of Friday night, greeting potential supporters, posing for pictures (there were many requests), and introducing himself as he tried to spread his message beyond his tiny Western Pennsylvania borough.

"Coming from Braddock, it's not my first choice of venues, but everyone's very nice," he said.

Under his button-down work shirt, he wore a tuxedo T-shirt.

Meanwhile, more conventional Democratic contender Katie McGinty didn't have to introduce herself - she is well-known among party insiders after running for governor last year and serving as Gov. Wolf's chief of staff. Instead, she touched base with old acquaintances.

At a fund-raiser for Sen. Robert P. Casey Jr. (D., Pa.,) - up for election in 2018 - McGinty exchanged hugs and handshakes with loyal Democrats, ribbing one about his new beard.

She also held a fund-raiser and tried to attract potential donors while skipping among numerous events.

"Mostly, it's reconnecting with old friends," McGinty said.

"It's a more relaxed environment," she added, allowing for "conversations where people feel like they can let their hair down a little bit. Some people let their hair way down."

Illustrating GOP fears, she used Trump's appearance to blast Toomey, saying the money raised by the state party would help the incumbent next year.

"The kind of ill will and hatefulness that [Trump] is injecting into our country is a dangerous thing, and I still call upon Pat Toomey to not profiteer on Trump's poison," McGinty said.

Republicans countered by criticizing McGinty for accepting endorsements last week from two Philadelphia councilwomen, Blondell Reynolds Brown and Jannie Blackwell, who paid fines for campaign-finance violations in 2012 and 2013 - though neither has Trump's clout, or figure to be significant factors in the race.

Steering clear of the New York scene was Sestak, who has run a grassroots campaign, ignoring the typical establishment playbook.

His campaign instead rented a U-Haul to deliver food and other items to needy people in the state capital.

He said federal funds to help schools and the poor have been frozen by the long state budget standoff.

"If you're a leader, you're with your people," Sestak said in a telephone interview. "I'm trying to demonstrate what's important."

@JonathanTamari