WASHINGTON — Another new poll found Democratic U.S. Senate candidate Katie McGinty leading Sen. Pat Toomey (R., Pa.) and — in a potential problem for the incumbent -- shows him running essentially even with Donald Trump.

McGinty has support from 43 percent of likely Pennsylvania voters, compared to 38 percent for Toomey, according to a Muhlenberg College/Morning Call poll released over the weekend. The same survey also found Trump with 38 percent support, trailing Democrat Hillary Clinton by 9.

The poll has a margin of error of 5.5 percent — suggesting that the Senate race is still close enough for either candidate to win. Other polls have also shown a tight race, with McGinty either leading slightly or the candidates effectively tied.

The Pennsylvania race appears increasingly important to deciding control of the Senate as contests in Illinois, Wisconsin, and Ohio look less and less competitive.

If Clinton continues Democrats' long winning streak in presidential races in the Keystone State, Toomey's fate will depend on running well ahead of Trump. But this poll, as well as other recent surveys from Monmouth University, Franklin & Marshall and CBS/YouGov show Toomey statistically even with the GOP nominee.

There was a recent exception: a Quinnipiac University poll earlier in September found Toomey with more support than Trump.

If Clinton wins by a margin close to 9 percentage points, operatives in both parties predict a difficult -- and perhaps impossible — struggle for Toomey down-ballot.

The Muhlenberg survey suggests that months of negative ads have taken their tolls on the two candidates. Toomey was viewed favorably by 28 percent of respondents, compared to 37 percent who view him negatively. McGinty was seen favorably by 23 percent against 28 percent who see her unfavorably.

The poll surveyed 405 likely voters between Sept. 12 and 16.

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