With just 40 days until Election Day — and with vote-by-mail ballots set to go out in just a week and a half on Oct. 8 — Democrats are eyeing at least a half-dozen California races as they work toward their magic number of 23 pickups needed to seize the House of Representatives.

And they’re dreaming of even more.

Republicans, meanwhile, are fighting back. They’re working to energize their voters while relentlessly attacking the Democratic challengers as unfit for office.

Still, California’s congressional contests could be determined by national events more so than anything the local campaigns do themselves.

“The president, his demeanor, what the country is facing nationally, has really been the overarching thing that we’ve seen in polling, where people are saying more so than ever before that the president is a major factor in their vote,” says NPR lead political editor Domenico Montanaro in a new episode of Keys to the House, Capital Public Radio’s podcast on the state’s battleground congressional races.

“The Trump factor has driven turnout to unprecedented numbers in a large part of the country,” adds Paul Mitchell, vice president of Political Data, Inc., a firm that analyzes and sells voter data to campaigns in both parties. “So I do think in these competitive congressional districts, we will see heightened turnout because of the national enthusiasm and excitement or anxiety or however you define it as a voter.”

The Cook Political Report, which tracks and rates congressional races, rates one California GOP district as leaning toward a Democratic pickup and five more as toss-ups.

Other seats, for Democrats, will be a much steeper climb.

A new Public Policy Institute of California poll points to an incredibly tight stretch run. Although likely voters statewide say they would vote for a Democrat in their local congressional district over a Republican by a 54-to-37 percent margin, voters in the 11 races considered competitive by the Cook Political Report are split: 44 percent Republican, 43 percent Democrat.

Here’s a look at the playing field:

For the data below:

• An asterisk denotes an incumbent member of Congress
• District PVI (Partisan Voting Index) and Rating are taken from the Cook Political Report
• June vote percentages listed are for each party’s “top two” nominee and for all of that party’s candidates combined in the primary

Already Blue?

Judging from outside spending — independent Republican groups have yet to spend a dime, according to the California Target Book, which tracks fundraising and spending by campaigns throughout the state — the GOP may have already be giving up on the seat currently held by retiring Rep. Darrell Issa (R-Vista).

A recent New York Times/Siena Research Institute poll showed Democrat Mike Levin with a 10-point lead over Republican Diane Harkey. And it’s the only battleground race in which the Democratic candidates combined to finish ahead of the Republicans in the June primary.

“That was something that was really shocking for a seat that has been essentially a safe Republican seat for years,” Mitchell says.

The SoCal Toss-Ups

These seats are shaping up to be Ground Zero in the battle for control of the House.

“If you’re going to see Democrats pick up those 23 seats, Democrats think they’ve got to get — if not all of these seats, most of them,” Montanaro says.

So Republicans and their allies are throwing the kitchen sink at the Democratic challengers. Outside groups aligned with the GOP have spent more than $4.5 million in the three districts combined, according to the California Target Book. Democratic groups are holding their own with about $4 million in outside spending.

Polls show tight races all around.

“To get two of these three, I think, would be a challenge for Democrats,” Mitchell added.

The Lone Central Valley Battleground

This largely rural district poses a different kind of race than the suburban Southern California districts, with dynamics in play that might be more similar to battleground seats in Middle America.

“A lot of the older whiter Democrats in (Central Valley) districts will vote for Republicans,” Mitchell says, while “the younger Democrats and younger independents are so low turnout.”

Outside spending in this race is roughly even.

Slipping Away?

Of these two races, Democrats have a stronger shot at the 39th district, which is being vacated by retiring Rep. Ed Royce (R-Fullerton). Democrat Gil Cisneros, a lottery winner, is significantly outspending Republican Young Kim on the campaign side. But he’s sliding under a heavy barrage of outside spending. Pro-Republican groups have spent more than $2 million attacking Cisneros, according to the California Target Book. Democrats aren’t exactly riding to his rescue, either; outside groups have only spent $64,000 on digital ads. A recent Monmouth University poll shows Kim with a four-point lead.

Montanaro calls Royce’s district “a place where Republicans have tried to look at and say, okay, here's how a diverse candidate can actually help win over the types of people who maybe should be Republicans but haven't been because of some of the national rhetoric.”

In the Central Valley, a look at the primary results suggests Democrats have very little chance of toppling Rep. David Valadao (R-Hanford). He nearly doubled up Democrat TJ Cox in the primary, despite the district’s Democratic bent.

“I don't think that the Valadao seat is extremely vulnerable for Republicans,” Mitchell says. “However, spending in these districts does essentially expand the playing field and create opportunities which might be necessary for Democrats to win the House.”

The Wildcard

It’s anyone’s guess how this race will turn out. It pits an indicted member of Congress, Rep. Duncan Hunter (R-Alpine), against an unknown challenger who isn’t getting much financial support from national Democrats.

“Because of the conservative bent of this district it's still an outside chance for Democrats to win here,” Montanaro says.

Wishful Thinking?

Democrats nationwide dream of knocking off Rep. Devin Nunes (R-Tulare), the House Intelligence Committee chair who’s one of President Donald Trump’s closest allies and a fierce critic of the Russia investigation. Democrats in Northern California dream of ousting Rep. Tom McClintock (R-Elk Grove), a staunch conservative who represents a district that sprawls from the northern and eastern Sacramento suburbs to the Nevada border. But both are considered long shots.

Any Vulnerable Dems?

The only two California seats held by Democrats considered to be at any sort of risk by the Cook Political Report are the 7th congressional district in the Sacramento suburbs and Fresno’s 16th district. Neither is considered likely to flip unless the blue wave fizzles out and a red wave crests instead.