Washington (CNN)Democratic candidate Conor Lamb is within 3 percentage points in a deep-red Pennsylvania congressional district ahead of a March 13 special election, a new Monmouth University poll shows.
National Democrats stay on the sidelines in close Pennsylvania House special election
Republican state Rep. Rick Saccone has 49% support to Lamb's 46% among likely voters in Pennsylvania's 18th Congressional District, the survey found.
The main reason for the tight race in a district President Donald Trump won by 20 points in 2016: Democrats are more likely to be interested in the race than Republicans -- and pollsters used a model based on turnout in last year's elections that projected higher-than-usual turnout in the Democratic-leaning Pittsburgh area. Using a model based on the lower-turnout 2014 midterm election, Saccone's lead jumps to 5 points.
Republicans are pulling out all the stops to save the seat ahead of November's midterms, where they hope keep Democrats from picking off 24 seats and taking majority control in the House.
Trump was planning a second trip to the district later this month, but postponed that visit Thursday out of respect for the victims of Wednesday's mass shooting at a Florida high school, his campaign said. Vice President Mike Pence has been there too. And Republican outside groups, fretting a close race, are spending millions to make sure the reliably red seat doesn't slip away.
But for Lamb, the Democratic cavalry hasn't come yet.
The leader of the House Democrats' campaign arm on Wednesday wouldn't commit to pumping any money into advertising in the district, which was formerly represented by Republican Rep. Tim Murphy, who resigned in a scandal last year.
"We'll continue to monitor that election day by day. But make no mistake: Conor will have the resources he needs to compete," New Mexico Rep. Ben Ray Luján, the Democratic Congressional Campaign Committee chairman, told reporters Wednesday.
Asked whether he believes Lamb can win, Luján deflected, saying: "I think Conor's fighting like heck."
With $1.3 million in ads, Lamb has outspent his Republican rival. But outside spending has overwhelmingly tipped in Saccone's favor.
The DCCC has spent more than $250,000 on TV ads in the race -- a small fraction of the Republican spending.
The National Republican Congressional Committee has spent or reserved $2.4 million, according to a source familiar with advertising buys in the race. The Congressional Leadership Fund, a super PAC aligned with House Speaker Paul Ryan, is in for $2 million. Two other GOP groups, the 45 Committee and Ending Spending, are topping $400,000.
Other Democratic groups have backed Lamb. The liberal blog Daily Kos -- which helped Jon Ossoff raise tens of millions in a failed Georgia special election last year -- endorsed him, while Massachusetts Rep. Seth Moulton has also backed Lamb and raised another $50,000 for his campaign at a New York event last week.
But the DCCC is staying out of the race even as it announces it has broadened its 2018 playing field and is now targeting 101 districts.
There are several reasons for Democrats to be wary about the Pennsylvania race.
It's a heavily GOP district. Trump won it by 20 points in the 2016 presidential election, and Mitt Romney bested Barack Obama there by 17 points in 2012.
Pennsylvania is also in the middle of a state Supreme Court-mandated redistricting process that could result in big changes to the state's congressional maps. Those changes would be implemented after the March 13 special election, but before November's midterms.
What that means: If the district is redrawn to favor Republicans even more, Democrats could win a seat now that they can't defend eight months later -- turning any money spent there into a waste. Or if it's redrawn as friendlier territory for Democrats, they could pick it off with less investment in November.
Still, for Republicans, the special election comes at a fraught moment -- with the party trying to regain its footing after passage of the tax bill, and at the tail end of a season of congressional retirements.
GOP ads there have tied Lamb, a 33-year-old former Marine and assistant US attorney, to House Minority Leader Nancy Pelosi, D-California, even though Lamb has said he doesn't support Pelosi.
"The only thing Conor Lamb will say is that he didn't support cutting taxes for hardworking Pennsylvanians and, folks, that says everything you need to know," Pence said during an early-February visit.
Trump is returning to Pennsylvania on February 21 to campaign for Saccone. Last month, the President tweeted that he was giving his "total support to RICK SACCONE," calling Saccone "a great guy."