President Donald Trump’s problems continue to mount, raising more questions about turnout and how independent voters and college-educated women will vote. But the Senate map remains daunting for Democrats, and the polarized nature of our politics continues to limit Democrats’ Senate prospects.

While handicappers generally label Nevada as a toss-up and the early polls are tight, the Democratic nominee, Rep. Jacky Rosen has an edge over incumbent Republican Dean Heller in a state that went narrowly for Hillary Clinton in 2016.

In Arizona’s open seat contest, Democratic Rep. Kyrsten Sinema has been the de facto Democratic Senate nominee for months, while Republicans have had a lively three-way primary. The frontrunner for the GOP nomination, Rep. Martha McSally, is a quality candidate, but her party is divided. Trump carried the state only narrowly two years ago, and his standing among the older, more affluent voters of metropolitan Phoenix certainly has not improved.

Sinema’s lead would narrow if Republican voters coalesce around McSally, but the Democrat has better overall positioning in the race and the edge in the race.

Republicans remain nervous about Tennessee, where the Democratic nominee, popular former Nashville Mayor and Gov. Phil Bredesen has a good reputation and appeal to independents and swing voters. Even Democrats are pleasantly surprised that Bredesen has been such a good candidate so far. But GOP nominee Marcia Blackburn is an aggressive campaigner, and the state’s strong Republican bent — Hillary Clinton drew only 35 percent of the vote — should eventually give her a boost. Bredesen probably has a slight edge now, but the state’s partisan landscape means he still has an uphill climb.

Finally, in Texas, some Democrats believe their challenger, Rep. Beto O’Rourke, is now a serious threat to incumbent GOP SenTed Cruz. The Democrat’s fundraising has been stunning, and recent polls from Quinnipiac and NBC News/Marist show the Republican incumbent with only a single-digits lead. But Cruz is at 49 percent in both surveys, and all of the other poll numbers suggest it will be all but impossible for O’Rourke to pull off an upset. Republican don’t seem very worried at all.

So, Democrats find themselves in virtually the same place they did months ago — needing to re-elect all or almost all of their incumbents up for re-election in November.

That was a tall, tall order six months ago, and it is a tall, tall order today.

A few of the 10 states that went for Trump in 2016 and have Senate races this cycle are not worth much attention. Democratic incumbents are expected to retain their seats easily in Michigan and Pennsylvania, and Sherrod Brown looks to be comfortably ahead in Ohio.

While a recent Marquette poll put Democratic incumbent Tammy Baldwin and Republican challenger Leah Vukmir in a near dead heat, other polling (non-public) suggests that Baldwin has a double-digit lead over her opponent. Given the problems of GOP Gov. Scott Walker, it’s likely that Baldwin has a comfortable advantage in this Senate contest and that even if the race narrows, the Democrats should hold onto this seat.

In Montana, which Trump won by 20 points, Democratic Sen. Jon Tester continues to have a solid lead, and the GOP challenger, state Auditor Matt Rosendale, isn’t one of his party’s top challengers. Even Democrats figure that the contest will close as November approaches, but for now Tester looks like he has a clear advantage.

That leaves five states that will likely decide Senate control. Democrats need to hold all of them, or “only” four out of five, depending on how other races fall .

The Democrats’ best chance of the five is West Virginia, a state that went for Trump by 42 points and gave Hillary Clinton only 26.4 percent of the vote. Incumbent Joe Manchin III’s numbers are holding steady in recent polling, and he has a surprisingly comfortable lead over GOP challenger Patrick Morrisey, the state’s attorney general. Republican attacks are likely to erode some of Manchin’s strong personal numbers, and the ballot test should close, but the Democrat is a well-known and well-liked figure in the state, and he has so far succeeded in swimming against the state’s Republican tide. Morrisey is a mediocre candidate.

The Republicans’ best chance is in North Dakota, which Trump carried by 35 points two years ago. Democratic incumbent Heidi Heitkamp is a strong campaigner, but the state’s profile — heavily rural, heavily Republican and heavily white — puts her in a hole against challenger Kevin Cramer, the state’s at-large GOP congressman.

Nathan Gonzales’ Inside Elections moved the race to tilting Republican in July, reflecting the challenges Heitkamp faces. This race certainly isn’t over, but the Democrat’s struggle looks uphill.

The three remaining races, Indiana, Missouri and Florida, are all toss-ups and close according to recent polling. Trump carried Indiana and Missouri by 19 points each, while Florida was a squeaker.

Of the three, Indiana’s Joe Donnelly may have the best prospects given voters’ views of his values and personal traits.

We should see some movement in all of these races after Labor Day, as the campaigns fully engage and the parties decide where to put their remaining dollars.

A blunder here or there could affect a race, and national news could impact who votes and what message they send in November. But at this point, Republicans have every reason to feel confident about the likelihood that they will keep the Senate in November. Only a substantial national Democratic wave would seem to threaten that outcome.

The column originally appeared in Roll Call on August 24, 2018.