Donald Trump’s campaign seems to be going down in flames — but it’s still far from clear how much that will help Democratic candidates in their effort to retake the Senate.

Democrats would need a net gain of four seats to retake the chamber if Hillary Clinton wins the presidency. And right now, they’re already likely to win two Republican-held seats, with five more looking like toss-ups. Then there is just one Democratic seat that appears to be up for grabs.

So depending on how those six toss-up races go, Democrats seem likely to end up with a net gain of anywhere between one and seven seats. And the difference between 47 Democratic Senate seats and 53 could be enormously consequential for a Clinton administration’s agenda and the balance of power on the Supreme Court.

Now, theoretically, if the bottom truly falls out for Trump and Republican candidates are dragged down with him, a couple more GOP-held seats could become competitive too.

But for now — and with Republican incumbents Mark Kirk in Illinois and Ron Johnson in Wisconsin already viewed as highly likely to lose — national Democrats have concentrated their attention and financial resources on these six toss-up contests:

New Hampshire , where Sen. Kelly Ayotte (R) is running against Gov. Maggie Hassan (D)

, where Sen. Kelly Ayotte (R) is running against Gov. Maggie Hassan (D) Pennsylvania , where Sen. Pat Toomey (R) is being challenged by Katie McGinty (D)

, where Sen. Pat Toomey (R) is being challenged by Katie McGinty (D) Nevada , an open-seat contest where Rep. Joe Heck (R) is running against former state attorney general Catherine Cortez Masto (D)

, an open-seat contest where Rep. Joe Heck (R) is running against former state attorney general Catherine Cortez Masto (D) Indiana , another open-seat contest where Rep. Todd Young (R) is pitted against former Sen. Evan Bayh (D)

, another open-seat contest where Rep. Todd Young (R) is pitted against former Sen. Evan Bayh (D) North Carolina , where Sen. Richard Burr (R) is facing a challenge from former state Rep. Deborah Ross (D)

, where Sen. Richard Burr (R) is facing a challenge from former state Rep. Deborah Ross (D) Missouri, where Sen. Roy Blunt (R) is being challenged by Missouri Secretary of State Jason Kander (D)

Some of these races haven’t been polled that often recently, and polls in some races have been all over the place (one recent poll shows Ayotte up 6, another shows her down 9). Also, there are rumblings that, in at least a few races, both parties’ private polling shows even more dire numbers for Republicans than we’ve seen publicly — though voters could well manage to disassociate Trump’s personal flaws from the Republican Party and split their tickets.

Overall, though, the public numbers we’ve seen so far suggest that while Democrats are within reach of taking the chamber, it’s far from a sure thing. For instance, FiveThirtyEight’s forecast gives Democrats a 71 percent chance of taking the chamber, while the Upshot gives them only a 60 percent shot.

In four swing races, Republican nominees are struggling to finesse the Trump issue

Four of these six swing Senate races are united by a common thread — they’re presidential swing states where Hillary Clinton appears to have gained an advantage, and where Democratic candidates are trying to tie their Republican challengers to Donald Trump.

Republicans facing competitive races all over the country have struggled over how to how handle Trump’s nomination. And, oddly enough, these four GOP nominees have all taken different approaches:

In New Hampshire, Kelly Ayotte bizarrely said for months that she’d support but wouldn’t endorse Trump. Earlier this month, she made an amusing gaffe by saying Trump would be a good role model for children and then walking it back. And after Trump’s “grab ‘em by the pussy” tape leaked, she finally ditched Trump altogether.

In Pennsylvania, Pat Toomey has simply refused to say whether he’d vote for Trump, saying that he hasn’t yet made up his mind.

In Nevada, Joe Heck backed Trump until the tape leaked. Then, he announced he’d no longer support the GOP nominee, and got booed. He was later recorded at a fundraiser saying that he was very conflicted and that he wanted to support Trump.

And in North Carolina, Richard Burr has long supported Trump, serves on a campaign committee advising Trump on national security, and recently reiterated that he still supports the nominee, saying “the choice is not close for me.”

Of course, these races are about more than just Trump — candidates and outside groups are spending on millions of ads trying to deem their opponents specifically unfit for office. (Deborah Ross “defends flag-burning!”) Catherine Cortez Masto is soft on crime! Pat Toomey supported NAFTA! Kelly Ayotte skipped half her Senate homeland security hearings!)

Still, these GOP candidates’ fortunes could well rise and fall with the GOP nominee. All four Republicans are currently outperforming Trump in polling averages in their respective states, with Ayotte and Toomey tending to outpoll him by 5 to 6 points, and Heck and Burr doing so by smaller margins. But if Trump continues to sink in these swing states, outpolling him by a few points may not be enough.

Meanwhile, Evan Bayh and Jason Kander are running in red states on reputation

But though there’s been so much conversation about Trump this year, two of the races that might help determine Senate control are occurring in red states that he’s still likely to win — in Indiana and Missouri.

When former Indiana senator Evan Bayh unexpectedly entered the race for his old seat in July, Democrats were thrilled. Bayh had over $9 million in his campaign account already and started off with a double-digit poll lead over the Republican candidate for the open seat, Rep. Todd Young.

But the race now looks very close indeed — one recent poll shows Bayh up by just one point, while another shows him up six. This tightening is likely in part because he’s been hammered about his decision to cash out by joining a lobbying firm, in part because he’s been dogged by questions about whether he’s really been living in Indiana, and in part because Republicans seem to have a natural edge in the Hoosier state (Trump still looks likely to win there). Democrats, meanwhile, have fired back with ethics attacks on Young, who’s run afoul of tax laws a few times, according to CNN.

In Missouri, meanwhile, Democrats have been thrilled with the performance of their candidate, Secretary of State Jason Kander. He’s a young, good-looking Afghanistan veteran who’s running as a fresh face (while also being a powerhouse fundraiser). Kander’s gotten a lot of attention for this ad in which he assembles an AR-15 while blindfolded:

Kander is challenging Sen. Roy Blunt (R) and arguing that Blunt, who’s been in Congress since the ‘90s, is the consummate Washington insider — he’s run ads pointing out that Blunt’s wife and three of his children are lobbyists.

Now, there hasn’t been much public polling of the Missouri race, and what little there is has tended to show Blunt ahead, but the New York Times reported recently that both parties’ internal polling now showed Kander ahead. Trump still looks likely to win Missouri, Kander’s personal appeal might well power him to victory.

Illinois and Wisconsin still appear to be gimmes for Democrats

Most observers don’t consider the races for Sen. Mark Kirk’s seat in Illinois and Sen. Ron Johnson’s seat in Wisconsin to be toss-ups — their Democratic challengers Tammy Duckworth and Russ Feingold have long led polls.

These two races have been at the top of Democrats’ target list all along. Illinois is likely to lean heavily Democratic in a presidential year, and Kirk had barely managed to win even during the 2010 GOP midterm wave — he’s now down by 9 in the HuffPost Pollster average. Johnson, meanwhile, has proved unpopular in Wisconsin, and the state’s voters seem set to restore Russ Feingold to his old seat — Feingold leads by an average of 5.8 points (despite a few recent polls showing a tighter race).

Furthermore, national groups from both parties have barely bothered to spend in either race, suggesting Democrats now feel assured of victory and Republicans have given up hope of holding these two seats.

But other races haven’t gone as well as Democrats once hoped

Still, not everything has been going so well for Democrats. Races in three states that the party once hoped to make competitive — Florida, Ohio, and Arizona — appear to have slipped away.

Florida is the one of these three that still looks the closest in public polls, with Sen. Marco Rubio (R) leading his challenger Rep. Patrick Murphy (D) by an average of six points. Yet the DSSC has gradually cancelled all the ads it had planned to run in the state, which some have interpreted as an admission that Murphy is likely headed to defeat.

In an interview, a national Democratic source characterized the decision to pull out of Florida as driven partly by money and partly by Rubio’s fame. Simply put, Florida is a big state where ad time is expensive, so money used to pay for a statewide buy for that race could instead be used to fund ads in several other less expensive but also competitive states. Furthermore, since Rubio ran for president and is already very well-known, Democrats think ads would be less useful in defining his image to his state’s voters than they would be for lesser-known figures in other states. “It’s a really expensive state if you think about the cost per vote,” the source says.

Ohio had also once seemed likely to be a marquee race this year, since incumbent Sen. Rob Portman (R) was being challenged by the state’s former governor, Ted Strickland (D). But Portman has, by all accounts, crushed Strickland — he’s now taken a massive 13.5 point lead in the swing states, in part due to ads reminding voters that Strickland was governor during the start of the state’s particularly painful Great Recession years.

National Democrats long ago abandoned Strickland, and some have bitterly complained about what they view as an underwhelming campaign effort from the 75-year old ex-governor. In September, the Columbus Dispatch reported that the DSCC’s executive director told a trade group that the state was no longer competitive, explaining it by saying, “Portman has run a damn fine race. The rest, I’ll have to tell you over a drink.”

Finally, in Arizona, Sen. John McCain (R) was recorded earlier this year saying that “if Donald Trump is at the top of the ticket,” this “may be the race of my life,” because he’d generate such a backlash among Hispanic voters. Democrats were hoping he was right, since Rep. Ann Kirkpatrick (D) was there to challenge him. And now, Hillary Clinton’s campaign is making a surprising late push in the state.

McCain still appears to be doing fine, though — even the recent polls showing Clinton ahead in Arizona have tended to give McCain a comfortable lead. On average, he’s up by 9 points, according to HuffPost Pollster. He did make headlines this week for saying he’d fight against anyone Hillary Clinton nominated to the Supreme Court, which seems to clash with his self-styled “maverick” image, but Democrats have had little luck turning the court issue to their advantage so far.

Still, though these races don’t appear to be the main battlegrounds, as long as Trump is still on the ticket — and as long as there are still days left for him to say outrageous things — none of these Republican senators will be too comfortable.