Anti-deportation protesters chant in front of the White House on Aug. 28, 2014. (Kevin Lamarque/Reuters)

With the exception of Colorado, there aren't that many Latinos living in states with competitive Senate races -- and there are even fewer Latinos living in House districts controlled by Republicans.In a fascinating thought experiment earlier this week, Nate Cohn determined that Republicans could hold a majority in the House without a single Hispanic vote.

The Hispanic vote does not appear to be damaging congressional Republican candidates all that much. On the contrary, those voters might be hurting Democrats, who desperately need their enthusiasm and support in some races.

Hispanic voters are frustrated with continued deportations and with what they see as the Democratic Party's failure on immigration reform. Only a narrow majority of Latinos say they approve of the job President Obama is doing, according to Gallup. His approval ratings among Latinos have fallen by 20 points since his reelection in 2012.

Much of the election analysis has been focused on control of the Senate, where Hispanics do have less influence over the outcome. But this year's gubernatorial races are arguably more consequential. In Kansas, for example, Gov. Sam Brownback's tax cuts have left the state with an expanding budget shortfall, but haven't obviously improved the economy.

In a dead heat like Colorado's gubernatorial race, Latino support is crucial for Democrats. A recent Quinnipiac poll put Gov. John Hickenlooper just one point ahead of his Republican opponent, former Rep. Bob Beauprez. Hispanics constitute fully 14 percent of eligible voters, so it's easy to see how a small change in turnout could sway the election. (About one in three eligible Hispanic voters have voted in past midterm elections, according to the Pew Research Center.)

Last month, one Latino advocacy group threatened to boycott the election, saying a program to issue driver's licenses to undocumented immigrants had been underfunded. All the same, Hickenlooper's campaign has had success in reaching out aggressively to the community, said Matt Barreto of Latino Decisions, a polling firm.

In Kansas, eligible Hispanic voters are only about 6 percent of the electorate, but the gubernatorial race might even closer. The polls are split on whether Brownback will survive a challenge from Paul Davis, a state legislator.

Even in some crucial Senate races, Latinos could be influential, but by not showing up at the polls. Take Sen. Kay Hagan (D-N.C.), whom the advocacy organization Presente Action targeted in a radio spot. Hagan voted with Republicans in a filibuster of the Dream Act in 2010, and more recently, sided with Sen. Ted Cruz (R-Tex.) in a failed procedural vote supporting deportations.

Barreto argues that Hagan's decisions on immigration won’t deliver the kind of swing voters she may have been targeting. Those voters are moderate on immigration anyway, he said. Now, less than half of Latinos are planning on voting for Hagan, according to his firm's research -- despite months of hard work by Democratic organizers.

Well-informed Latinos are understandably frustrated with Hagan and other Democrats, Barreto said. If they don't vote, he added, "it’s because they’re paying attention." Most models give Hagan a comfortable, if narrow, lead, and Latinos are only about 3 percent of eligible voters in North Carolina, so she may well survive without the ardent support of the Hispanic community.

The Latino vote might not be decisive in North Carolina or in any other state, the way it could be in 2020, when as many as 25 million more Hispanics will have joined the electorate.

What's in Wonkbook: 1) Ebola arrives in New York 2) Opinions: Obamacare, G.O.P. governors, IBM and the female vote 3) The Republican agenda 4) Leaks in the Ferguson, Mo. investigation 5) Defective airbags, Arkansas demographics and more.

Number of the day: 8, usually 7That's how many rounds fit into the Winchester deer-hunting rifle that Michael Zehaf-Bibeau used to attack the Canadian Parliament Wednesday. Assault rifles and automatic weapons are banned north of the border. Evan Dyer for CBC.

Chart of the day:

water rates

Water in Seattle is about three times as expensive as it is in El Paso. No wonder farmers and households use the wet stuff so inefficiently, despite the historic drought in the Southwest. Rebecca Leber in The New Republic.

1. Top story: Doctor isolated with Ebola in New York City

The physician, Craig Spencer, had recently returned from Guinea, where he was treating victims of the disease. Authorities have quarantined his fiancée and two friends, but do not believe that he was contagious before he was isolated with a fever on Thursday. The Centers for Disease Control and Prevention are conducting a second test to verify an initial positive result. Marc Santora in The New York Times.

The virus has also arrived in Mali for the first time. A 2-year-old girl who traveled from Guinea has tested positive for the virus. Francois Rihouay and Simeon Bennett for Bloomberg.

Two vaccines could be ready for large-scale trials early next year, but ethical and practical questions remain. At this point, immunization could be the best hope of controlling the epidemic in West Africa, but GlaxoSmithKline's vaccine has to be stored at -112 degrees Fahrenheit. And while early trials don't show any negative side effects, it isn't clear yet whether it can really prevent infection, and organizing a large-scale trial in a place like Liberia right now would be difficult. Brady Dennis in The Washington Post.

One vaccine sat on the shelf for a decade after highly successful testing in monkeys. Fully developing and testing a vaccine in humans typically costs more than $1 billion. "There's never been a big market for Ebola vaccines," said one of the researchers. "So big pharma, who are they going to sell it to?" Denise Grady in The New York Times

In one of Liberia's poorest slums, neighbors are coming together to fight the disease. Shoes and socks, plastic bags for gloves, and buckets of bleach are volunteers' weapons against Ebola. The scene in the West Point district of Monrovia has changed from a few weeks ago, when residents thought the disease was a hoax and flouted quarantines. Heidi Vogt in The Wall Street Journal.

GERSON: We are in collective denial about the horrific danger posed by Ebola in West Africa. As many as 10,000 new cases a week are expected by December, the global community hasn't begun to ask the most important questions: "Is Ebola containable? Will we see disease-related hunger? How will rice crops be harvested and transported? What effects will spiking food prices have on civil order? Might there be large-scale, disease-related migration? What would be the economic effects on all of Africa?" The Washington Post.

2. Top opinions: Obamacare, Republican governors, IBM and female voters

FRIEDERSDORF: What exactly is Keith Alexander selling? A lawmaker asks how the National Security Agency's former director can offer banks expensive consulting services, unless what they're paying for is classified information. The Atlantic.

DOUTHAT: Conservatives are missing their opportunity to repeal and replace Obamacare. They've shied away from offering concrete alternatives, wary of the political risks, but as the law will only become more ingrained in society with time. The New York Times.

MARK MILLS: Falling oil prices are no danger to the booming U.S. gas industry. Engineers keep finding more efficient ways to get natural gas out of shale formations. High-resolution imaging, laser-guided drilling and more maneuverable drill bits will keep the fossil fuel flowing. The Wall Street Journal.

IGNATIUS: The Islamic State is gaining ground. Tribal leaders say help promised by American officers didn't arrive before the militants took strategic towns, and disaffected Sunnis are joining their ranks. The Washington Post.

JEFFREY SACHS: Economic growth requires a carbon policy. The way to stimulate sluggish demand for investment is to set clear, precise goals for limiting carbon dioxide emissions and modernizing the electrical grid. Project Syndicate.

STRAIN: Janet Yellen is becoming a partisan hack. The head of the Federal Reserve has no business entering into political debates over inequality. Investors will distort markets if they no longer believe the central bank is politically independent. The Washington Post.

KRAUTHAMMER: Obama's lack of experience in management shows. The president can't pretend to be an innocent, outraged bystander when his own government makes mistakes. The Washington Post.

3. A look ahead at the Republican agenda in Congress

Republicans plan to demolish Obama's legacy if they win the Senate. They'll try to restrain the Environmental Protection Agency's authority on carbon dioxide, as well as force an approval of the Keystone XL pipeline and open public lands for more drilling. They can't repeal Obamacare while the president is still in office, but they aim to weaken the employer mandate. Steven Mufson in The Washington Post.

They're attacking Democrats for cutting Social Security, which could complicate entitlement reform. In what you could call an ironic twist of fate, Democrats who supported the Simpson-Bowles compromise have been accused of betraying senior citizens. The attacks will make any entitlement reform more difficult politically for both parties after the election. Lori Montgomery in The Washington Post.

Polls show Republicans making gains among women in close Senate races. Some recent polls show Rep. Cory Gardner in Colorado and Rep. Tom Cotton in Arkansas ahead of their opponents among women. Democrats are relying heavily on the female vote. Janet Hook in The Wall Street Journal.

At the same time, winning over black voters hasn't gotten any easier. The Republicans ought to be able to reach blacks, who are more likely to describe themselves as conservatives than as liberals, on issues such as charter schools, abortion and gay marriage. Yet many blacks detect racism in Congressional Republicans' relationship with Obama and Attorney General Eric Holder. Meanwhile, there is the uncomfortable fact that there is only one black Republican in Congress. Siobhan Hughes in The Wall Street Journal.

4. Amnesty International condemns police in Ferguson

A report claims law enforcement officers violated demonstrators' human rights. According to Amnesty International's report, officers' reliance on tear gas and rubber bullets as well as restrictions on peaceful protest breached international norms. The report also criticized Missouri law, which permits police to use deadly force in making an arrest if they believe the suspect committed a felony. Carey Gillam for Reuters.

Meanwhile, Attorney General Eric Holder feels that information leaked to the press was "selective." The details of the autopsy report and witness testimony, which were published in papers including The Washington Post, all appeared to support Officer Darren Wilson's accounting of the shooting of Michael Brown. Holder has told his subordinates that he is "exasperated." Robert Samuels and Sari Horwitz in The Washington Post.

The fact that the autopsy showed Brown had marijuana in his body says nothing about why he died. Marijuana is not correlated with violence and aggression. Although sources told The Washington Post that Brown had enough THC in him that he could have been hallucinating, hallucinations are rare with marijuana. The drug might have made Brown confused and anxious if he had just used it, but marijuana can remain in a person's body for days. Christopher Ingraham in The Washington Post.

COHN: Wilson was never likely to be indicted. Under the lenient standards of Missouri law, a successful prosecution would be nearly impossible. The New Republic.

5. In case you missed it

Markets have calmed down since last week, but there are still reasons to be nervous. Oil and food prices are depressed, and investors are no longer sure that the Federal Reserve will raise interest rates next year, all signs of widespread pessimism. At the same time, indicators, such as unemployment, suggest the economy is still slowly recovering. Neil Irwin in The New York Times.

Three House Democrats offer three different proposals on net neutrality. After a court struck down net neutrality rules earlier this year, policymakers are paging through the statutes in search of a different legal approach. Brian Fung in The Washington Post.

The new streetcar in the nation's capital is worse than a waste of money. It will actually make public transportation less efficient in Northeast Washington. The streetcar shares a lane with existing bus routes, and the vehicles will interfere with one another. Matthew Yglesias in Vox.