I continue to keep an eye on the vulnerable Republicans in the Senate because the Democrats only need four seats to retake the majority. Not helpful is that Hillary and her campaign hope to raise $1 billion to help unseat vulnerable GOP senators.

Their efforts may not come to fruition as Sen. Jon Tester (MT), the campaign chairman for the Senate Democrats, sounded the alarm on Wednesday. He claimed the party could only regain three seats if they held elections today.

The Hill reported:

While Senate Democrats have a favorable electoral map, they say a deluge of spending from outside groups has buoyed vulnerable Republican incumbents such as Sen. Rob Portman (Ohio), who had been a top target.

The DSCC and Senate Majority PAC, a Democratic super PAC, recently canceled advertising buys in Ohio.

Tester sees Illinois, Wisconsin and Indiana as three slam-dunk races for the parties. But other states — New Hampshire, Pennsylvania, Florida and Ohio — are turning out to be much tougher than anticipated.

Republicans scored a coup in June when they convinced Sen. Marco Rubio (R) to run for reelection, greatly boosting their chances of keeping his Florida seat.

But as The Hill pointed out, this also shows the Democrats worry more about the Senate than the White House.

Democrat Vice Presidential candidate, Tim Kaine (VA), tried to raise Senate Democrat spirits by telling them that he and Hillary can beat Donald Trump. But Tester is still worried:

“The way we’re approaching it at the DSCC is every race is in the mix and we’ve got to work our butts off and make sure the candidates are working their butts off,” he said. “We’ve got a good chance of getting the majority, but it’s not a slam dunk.”

He is not the only one:

Behind closed doors, Tester, Sen. Charles Schumer (N.Y.) — who would likely become majority leader if Democrats recapture the Senate — and retiring Senate Democratic Leader Harry Reid (Nev.) offered a sober view of the likelihood of winning back the upper chamber, lawmakers said.

They painted a worrisome picture of a political landscape awash with advertising dollars from Republican-leaning outside groups such as the Senate Leadership Fund and One Nation, which reported raising $42 million in August alone.

Schumer even said he would give $2 million from his campaign to help out.

Should the Democrats worry? Yes. Republicans have started to pour funds into GOP Senate races, including $14 million to help Sen. Kelly Ayotte (R-NH). From The New York Times:

In North Carolina, the One Nation advocacy group just poured $1 million into an ad buy in support of Senator Richard M. Burr, a Republican who has been buffeted by Mr. Trump’s difficulties in the state. That was on top of a $1.5 million infusion weeks before.

The group, which does not disclose its donors, is run by allies of Senator Mitch McConnell of Kentucky, the majority leader, and Karl Rove. It has already spent at least $25 million on other close Senate races, including those in Pennsylvania and New Hampshire.

The Freedom Partners Action Fund, a “super PAC” aligned with Charles G. and David H. Koch, has spent at least $15 million on TV ads, a quarter of it in Pennsylvania, where Senator Patrick J. Toomey is in a tough re-election fight, at least in part because of voters’ distaste for Mr. Trump.

Here is where some of those Senators stand:

Sen. Kelly Ayotte (R-N.H.) trails Democratic Gov. Maggie Hassan by 1 point while Trump lags Clinton by 9, Sen. Pat Toomey (R-Pa.) is less than a point behind Katie McGinty while Clinton leads by nearly 7 points and Sen. Rob Portman (R-Ohio) is outrunning Trump by 10 points with a healthy lead over former Gov. Ted Strickland, according to RealClearPolitics polling averages. But if Trump were to sink further in the polls, all that could change.

But since the GOP candidates have such a large lead in Ohio and Florida, Democrats now know they must target these other states:

“We have many states that are within 1 or 2 points. It’s the challenge of having too many good races,” said Sen. Debbie Stabenow (Mich.), a member of the Democratic leadership. “But the big challenge at this point is all the huge special-interest money — big oil — that has decided it’s not going to give to Donald Trump and going to put it all on the Senate races.

“They are desperate to hold on to the Senate to protect that open Supreme Court seat,” she said, referring to the vacancy left by the death of conservative Justice Antonin Scalia.