Republicans hoped to score an upset win Tuesday in a special congressional election for a heavily Democratic area of New York, sending President Barack Obama an ominous message.

The 9th Congressional district in New York City's Queens and Brooklyn boroughs came open in June when the popular Democratic incumbent, Anthony Weiner, resigned over revelations that he was sending X-rated photos of himself to women he met online.

As if the clean-cut, married congressman's sex scandal was not embarrassing enough, Obama's party now risks the humiliation of losing a seat in a district where registered Democrats outnumber registered Republicans 3:1.

The latest numbers from Public Policy Polling show Republican businessman Bob Turner leading veteran Democratic state and city legislator David Weprin by 47 to 41 percent.

Such a result would be seen as another dent in Obama's battered armor as the president gears up for reelection next year while grappling with deepening discontent over unemployment and his own performance.

"It would be," said Steven Brams, politics professor at New York University. "The expectation, because that's a heavily Democratic district, is of course that the Democrat will win. Anthony Weiner won by substantial margins in his race."

Analysts say that one clear reason for Weprin's struggle is his association with Obama, who has only a 45 percent approval rating nationally.

"If Turner wins on Tuesday it will be largely due to the incredible unpopularity of Barack Obama dragging his party down in the district," PPP said.

Another big factor could be the outsized influence in this district of the Jewish vote. Turner has homed in on the large Orthodox Jewish community and could have success in reversing the usual Democrat leanings of Jews.

Conservative Jewish-Americans have long been suspicious about the water-tightness of Obama's support for Israel, so Turner has campaigned as a fervent pro-Israeli, as well as a social conservative in contrast to Weprin, who voted as state assemblyman for gay marriage in New York.

Turner has also resurrected last year's incendiary controversy about plans for construction of an Islamic center two blocks from Ground Zero in lower Manhattan.

Obama, New York's Jewish mayor, Michael Bloomberg, and others supported the project as an expression of freedom of religion, which is protected by the constitution.

But right wing politicians warned of nothing less than an Islamist militant bridgehead at the site of the former World Trade Center, where nearly 3,000 people died a decade ago in the al-Qaeda terrorist attack.

Turner picked up on that theme in a flier depicting a huge mosque over the smoking rubble of Ground Zero and noting Obama and Weprin's support.

"Regardless of who wins on Tuesday," Matt Brooks, head of the Republican Jewish Coalition, said in a statement, "Jewish voters in NY-9 will send a clear message to President Obama and the Democratic Party."

Turner has won the support of a former New York mayor and lifelong Jewish Democrat, Ed Koch.

But Weprin is also fielding some big guns, with automated phone messages urging votes for him from former president Bill Clinton and current New York Governor Andrew Cuomo, USA Today reported. He will be able to count on the district's Democratic machine and union votes.

Also, while the New York Post tabloid has plumped for Turner -- partly over the Israeli issue -- the New York Times has given its backing to Weprin.