(CNN) House forecast: Democrats will win 228 seats (and the House majority) while Republicans will win just 207 seats. A Democratic win of 205 seats and 263 seats is within the margin of error.

Democratic hopes to take back the Senate remain lousy. A big reason why is that they cannot put away the races they need to win even to be in a position to score some upsets.

Earlier this week, I noted all the close Senate races. As of this writing, there are four races that are forecasted to be 2-point margins or less when all the votes are counted: Arizona, Florida, Missouri and Nevada.

All but Nevada are favored to go the Democrats way. Now that may seem like good news for the Democrats. It's actually anything but good news.

Let's say the Democrats were able to sweep those races. That would still leave them in control of only 50 seats next year. They need 51 for control.

Of course, it's unlikely that the Democrats will win all of these races. Our model actually thinks it's more likely that Republicans will win one of the very close races they are forecasted to lose than the Democrats are to win one of the races they're forecasted to lose. That's because there are more opportunities for Republicans to pick off a close seat than there are for Democrats.

Worse for Democrats, it's not clear at all that Democrats are gaining in any of these close races either. They may be losing ground.

In Arizona, Democrat Kyrsten Sinema led in seven straight non-partisan polls during September. She's only led in two of the last four polls.

In Florida, Democrat Bill Nelson led in five straight nonpartisan polls during September. He's trailed in the last two polls out of the Sunshine State.

In Missouri, Democrat Claire McCaskill was down in only one nonpartisan poll between mid-March and early September. She's only led in one poll since that point.

In Nevada, Democrat Jacky Rosen trailed in only two nonpartisan polls completed before mid-September. She's been down in four of the last five.

The model still gives Democrats a decent chance of winning these races because, in part, it doesn't dismiss older polling entirely. If the polling continues to be lackluster in the final days, the forecasted margins will move the Republicans way.

But let's say Democrats win all of these races. They are, as I said, one short of a majority.

The most obvious suspects to pick off a seat are North Dakota, Tennessee or Texas. Democrats are forecasted to lose by 4 points in all of them. In other words, their deficit is worse in these four then it is in the close races. It also seems to be getting worse by the day.

In North Dakota, Democrat Heidi Heitkamp hasn't led in a poll since February. She's been down double digits in the last two polls released in the race.

In Tennessee, Democrat Phil Bredesen has been down in all four polls finished in October. In September, he led in two polls and trailed in two.

In Texas, Democrat Beto O'Rourke has been, on average, 7 points behind in polling conducted this month. He was down only 3 in an average of polls last month.

The bottom line is that yes Democrats still have a path to the Senate majority. Our forecast still gives them an outside shot of controlling 53 seats. That, though, is improbable. Democrats are having a tough enough time locking down the seats they need to even be in a position to get a majority, let alone make a comeback for the additional seat they need to get it.