Mandela Barnes, left, and Ron Johnson, right.
CNN  — 

After Tuesday’s primaries, the general election matchups for the Senate races that are expected to be the most competitive this fall are now set.

In Wisconsin, Lt. Gov. Mandela Barnes officially became the Democratic nominee for US Senate. He will face Ron Johnson, the incumbent Republican senator Democrats view as the most vulnerable this year.

Last month, CNN ranked Johnson’s seat as the fifth most likely to flip party control in the midterm elections. Here is how the rest of the races in the top five shook out:

1. Pennsylvania: Lt. Gov John Fetterman (D) vs. celebrity doctor Mehmet Oz (R)

2. Nevada: Sen. Catherine Cortez Masto (D) vs. former state Attorney General Adam Laxalt (R)

3. Georgia: Sen. Raphael Warnock (D) vs. former football player Herschel Walker (R)

4. Arizona: Sen. Mark Kelly (D) vs. venture capitalist Blake Masters (R)

Of the rest of the races in the top 10, only two other November matchups are yet to be finalized. In New Hampshire, ranked sixth on the list, Democratic Sen. Maggie Hassan won’t know who will emerge from a field of relatively unknown Republican candidates until mid-September. And in Florida, number eight in the rankings, Rep. Val Demings is the heavy favorite to win the August 23 Democratic primary to take on GOP Sen. Marco Rubio.

As the landscape becomes clearer 90 days out from Election Day, there are reasons for Democrats to start feeling slightly more optimistic about their chances of keeping control of the 50-50 Senate.

At the macro level, the stiff headwinds the party has faced for most of the cycle may be starting to abate somewhat.

While recent polls suggest President Joe Biden’s approval ratings are still abysmal, he has finally started to string together some legislative victories. This week, he signed bills into law aimed at boosting American chip manufacturing and expanding health care benefits to military veterans who were exposed to toxic burn pits. The Senate also passed a major climate, tax and health care bill over the weekend, which will likely head to Biden’s desk after the House takes it up in the coming days.

The economy – voters’ top issue – remains in rough shape, but there have been signs in recent days that conditions could be improving. Inflation slowed in July, the latest monthly jobs report showed a higher-than-expected gain, as gas prices are continuing to drop. And a resounding victory for abortion rights advocates on a Kansas constitutional amendment last week has Democrats feeling confident that they can use the issue to their advantage.

There are some positive indicators at the individual race level Democrats can point to as well.

In the five most hotly contested races listed above – all of which are in states Biden won in 2020 – incumbent Democratic senators are vastly outraising their Republican opponents in three of them (Nevada, Georgia and Arizona). In Pennsylvania, Fetterman, who has opened up an early polling and fundraising advantage, is scheduled to return to the campaign trail this week after suffering a stroke in May. And in Wisconsin, Democrats were already largely united behind Barnes after his main primary opponents dropped out in the final stretch of the race.

Republicans also took risks by nominating first-time candidates like Oz, Walker and Masters, all of whom have already found themselves embroiled in controversies.

Even Senate Republican leader Mitch McConnell tempered expectations during a recent appearance on Fox News. “I think it’s going to be very tight,” he said. “I think when this Senate race smoke clears, we’re likely to have a very, very close Senate still, with us up slightly or the Democrats up slightly.”

This is all not to say Democrats have somehow completely turned the tide heading into the fall. But it does underscore that the playing field for the Senate is much more fertile for the party than the House. The latest forecasts from FiveThirtyEight show Democrats have a 60% chance to maintain control of the Senate, compared to just a 20% chance to hold the House.

The Point: The main question hanging over the battle for the House during the next three months will likely be not whether Republicans will win the majority, but by how much. The battle for the Senate, however, looks like it will go down to the wire.