Could the GOP retain control of the Senate despite defending fourteen more seats in the upcomimg election? According to the initial ratings on the 34 races from the Washington Post, the answer is yes. However, the operative condition on Aaron Blake’s analysis is right now:

According to The Fix’s debut ratings of the 34 seats up this year (24 of which Republicans are defending), two GOP seats are currently leaning towards Democrats, in Illinois and Wisconsin, but Republicans have otherwise cut down on their potential losses.

As of now, we list just four races as toss-ups: Indiana, Nevada, New Hampshire and Pennsylvania. Given Republicans currently have an effective 54-46 majority, Democrats would have to win three of those four toss-ups if Hillary Clinton wins the presidency — Vice President Kaine would be the tie-breaker in a 50-50 Senate — and all four if Trump wins the presidency.

This all comes with a large caveat, and that is this: There are many other seats Republicans have to defend — ones that could become more competitive again, especially if Trump falters.

In fact, we currently list a grand total of eight seats as “lean Republican,” and some of them are teetering on the edge of being toss-ups. Polls have shown both Sens. Roy Blunt (R-Mo.) and Richard Burr (R-N.C.) in tight races in recent weeks, and Sen. Marco Rubio (R-Fla.) can hardly be called a shoo-in at this point.

The latter race has suddenly caught the interest of Politico’s Seung Min Kim, who claims that the GOP is “fretting” over Burr:

Republicans are privately fretting that the laid-back Burr isn’t campaigning aggressively enough for his third Senate term and potentially risking a GOP seat that the party should otherwise have in the bag. But — in his usual easygoing form — Burr brushed off any concerns about national Democrats spending at least $6.7 million to unseat him — a forceful play to make a red-leaning state competitive less than two months before the election.

“It’s great. I think anytime they waste money it saves my colleagues from having it go after them,” Burr smirked when asked of Democrats’ money blitz. “Am I complaining that the last [Quinnipiac] poll had me up 6? No! I’m probably in better shape than we dreamed.”

The Senate Intelligence chairman risks getting caught flat-footed against a relatively unknown opponent in North Carolina, which has become a major target for Democrats eyeing the White House, Senate and the governor’s mansion in Raleigh.

Two relatively recent polls show Burr getting edged by Deborah Ross, one from Elon that dropped this week and a CBS News/YouGov poll from the beginning of the month. By traditional measures, Republicans might be right to worry. The only September poll that shows the incumbent above 43% is the one from Quinnipiac that Burr cites. That’s a low number for incumbents in any race, and perhaps especially so in such an evenly divided state as North Carolina. The upside for Burr is that he’s won in North Carolina before, and the RNC has laid down an extensive ground game for candidates up and down the ballot, so the Democrats’ investment there isn’t going unmatched.

That’s also true for the other Senate races in the WaPo mix, too. At least at the moment, the presidential races haven’t weighed on down-ballot candidates, as seen by the significant difference in support for these Senate candidates and Donald Trump in these states. With Trump taking the big-rally/national-message approach, there’s a lot more bandwidth for the RNC ground game to work on behalf of candidates like Marco Rubio, Kelly Ayotte, and Pat Toomey.

Of course, it helps that the DNC and DSCC didn’t do a great job in candidate recruitment in some of these races, too. Democrats thought they had the Florida seat wrapped up until Rubio jumped in at the last minute to run for re-election. Even without the popular incumbent in the race, their nominee looks particularly vulnerable — and the GOP-backing Senate Leadership Fund will spend $10 million making sure Floridians know it:

A powerful outside group backing Senate Republicans is launching on Tuesday a $10 million campaign attacking the Democrat challenging Sen. Marco Rubio (R-Fla.).

The Senate Leadership Fund, a super-PAC with close ties to Senate Majority Leader Mitch McConnell (R-Ky.), is aiming to portray Rep. Patrick Murphy (D-Fla.) as a serial liar who fabricated his résumé.

The DSCC has backed out of ad commitments in Florida, so Blake’s caveat on Rubio’s lead looks pretty pro forma. With the DSCC bailing on Murphy, Democrats in the state want Harry Reid’s Senate Majority PAC to fill the gap — and so does Murphy’s dad Thomas, who dropped a cool million bucks into its coffers last quarter. We’ll see if Murphy père gets his money’s worth out of that investment.

If the GOP can maintain this advantage all the way to November 8th and keep control of the Senate, it will count as one of the more significant national political upsets in recent memory. Considering the volatility of the 2016 cycle, though, that’s still a big if.