Cash blitz could boost Democrats' House chances, but their hopes of taking the Senate remain slim

As voters prepare to cast their ballots in pivotal midterm elections in 18 days, split control of Congress appears to be the most likely outcome.

In the past week, Democratic House candidates have unveiled massive fundraising numbers that could give them more momentum toward seizing the chamber on Nov. 6, according to top forecasters. The battle for the Senate could not look more different. Prognosticators believe Republicans have a strong grasp on the chamber despite the House trends.

Democrats have to flip a net 23 GOP-held House district to take a majority, and nonpartisan experts think the target is well within the party's reach. Winning the two net seats needed to flip the Senate while facing a brutal map is much more difficult for the party.

The cash blitz — a gauge of voter enthusiasm and campaigns' ability to get out the vote — has given Democrats a bump. At least 90 Democratic candidates raised more than a GOP incumbent, while about 65 raised more than $1 million, according to the National Journal.

Despite the Democrats' and Republicans' respective edge in the fight for the House and Senate, nothing is assured with only 2½ weeks of campaigning to go. If the GOP hangs on in only a handful of toss-up races, it could cling to control of the House. Similarly, if multiple Senate races swing the Democrats' way, the party could pull off a Senate upset.

Here's how top forecasters viewed the battle for Congress as of Friday morning:

• A wide battlefield will determine control of the House. Prognosticators consider about 70 or more of the 435 House districts competitive. The GOP controls the vast majority of those seats and has a strong chance to win in only a few Democratic-held districts.
• Democrats have more than an 8 percentage point advantage in an average of recent generic ballots, which ask voters to choose which party they want to control Congress, according to data journalism website FiveThirtyEight. The advantage is almost exactly the same as it was a week ago.
• The party has more than an 84 percent chance of seizing control of the House, with an average projected gain of 39 seats, according to FiveThirtyEight's "classic" House forecast. The model takes into account factors such as polling, past voting trends and fundraising. Democrats' chances have climbed from about 79 percent a week ago, partly due to their fundraising success. While it gives Democrats a very good chance of taking control, flipping the House is hardly a lock. Dave Wasserman, the House editor at the nonpartisan Cook Political Report, tweeted Thursday night that he thinks FiveThirtyEight's model could be "reading a bit too much" into the fundraising "bonanza."
• Democrats are currently favored to win 16 GOP-held districts in November, while Republicans have an edge in races for two seats controlled by Democrats, according to the Cook ratings. If those contests go as expected, it would amount to a net gain of 14 seats for the minority party — the same number of flips its ratings suggested last week. Democrats would then have to take a net of nine other seats out of the 31 districts considered toss-ups or the remaining 24 listed as "lean" Republican.
• Democrats have an advantage in 212 races, according to the nonpartisan Larry Sabato's Crystal Ball. The party would have to flip another six net seats out of the 22 contests the site lists as toss-ups to take a majority. A week ago, Sabato listed 210 districts as favoring Democrats.
• A third nonpartisan forecaster, Inside Elections, projects a most likely outcome of 25 to 35 seats gained by Democrats. The range is unchanged from last week.

Analysts saw a handful of races shifting in the past week. Among them is Minnesota's 8th District, a seat with a long Democratic tradition where incumbent Rep. Rick Nolan is not running for re-election. Both Cook and Sabato moved the contest to lean Republican.

President Donald Trump carried the seat in the state's Iron Range by 16 percentage points in 2016 after President Barack Obama won it twice, according to Cook. Republican Pete Stauber, a St. Louis County commissioner and former police officer, led Democratic former state Rep. Joe Radinovich by double digits in a recent New York Times/Siena College poll.

The two forecasters both view another race as drifting away from a Republican incumbent. They changed their rating on Illinois' 6th District, a suburban seat outside of Chicago, to lean Democrat.

Rep. Peter Roskam could become a casualty of backlash from white, educated voters that suburban GOP representatives face across the county. The GOP tax plan, which Roskam helped to craft, has not resonated as much as he would have hoped as he tries to hold off Democratic newcomer Sean Casten.

• Forecasters believe about 10 Senate seats — in Arizona, Florida, Indiana, Missouri, Montana, Nevada, North Dakota, Tennessee, Texas and West Virginia — are the most likely to flip this year. Democrats hold six of those, while Republicans control four. But polls have moved away from Democrats in two of the contests: Democratic Sen. Heidi Heitkamp's defense of her seat in pro-Trump North Dakota, and Rep. Beto O'Rourke's bid to upset GOP Sen. Ted Cruz in red Texas.
• The GOP has about an 80 percent chance of keeping control of the Senate, only a slight dip from a week ago, according to FiveThirtyEight. Republicans' chances of holding the chamber roughly mirror their chances of losing the House, according to the site. The GOP currently holds a 51-49 majority in the Senate.
• Cook considers eight of those 10 key races toss-ups. On Friday, it put Heitkamp's seat in the lean Republican column. It also lists Democratic Sen. Joe Manchin's re-election bid in West Virginia as one that leans Democratic. If those races hold, Democrats would have to carry out the daunting task of flipping three of the four GOP-held seats in Arizona, Nevada, Texas and Tennessee, while not losing any more of its own toss-up contests, to flip the two net states needed to take a majority.
• Sabato also favors the GOP to flip North Dakota and hold Tennessee and Texas. In addition, it gives Manchin the edge in his re-election campaign. Again, the forecaster shows a difficult path to Democrats winning a Senate majority.

Cook's downgrade of Heitkamp's re-election chances was only the latest hit for the Democratic incumbent. Sabato had already moved the race to leans Republican as polls increasingly show an advantage for GOP Rep. Kevin Cramer in a state Trump won by more than 30 points.

Polls had recently moved away from Democratic former Gov. Phil Bredesen, who hopes to beat GOP Rep. Marsha Blackburn and flip a red Senate seat in Tennessee. Then on Thursday, a survey showed Bredesen is still in the hunt.

A Vanderbilt University poll found him leading Blackburn by 1 percentage point. It is unclear now whether the survey is an outlier or a sign the state is still in play.

Meanwhile, a race where Republicans appeared to have a stunning chance for an upset has reset in favor of Democrats. Democratic Sen. Bob Menendez's polling lead in blue New Jersey had evaporated in recent months, as Republican former pharmaceutical CEO Bob Hugin spent heavily to hammer the senator over corruption charges that ended in a mistrial.

Monmouth University and Quinnipiac University polls this week found leads of 9 and 7 percentage points, respectively, for Menendez. In a sign of the race's competitiveness, a pro-Senate Democratic super PAC on Tuesday said it would drop $3 million into New Jersey on an ad tying Hugin to Trump.