To quash what he described as "irrational fear," New York Gov. Andrew Cuomo said Friday he'll ride one of the three subway lines taken by the latest Ebola patient in the United States.

"There's no reason for New Yorkers to panic of feel that they have anything to worry about on the subway system," the Democrat told CNN's Alisyn Camerota on "New Day," adding that he plans to ride either the A, L or 1 train on Friday.

Craig Spencer, a doctor who recently returned from Guinea, tested positive for Ebola on Thursday in New York, becoming the fourth person diagnosed with the virus in the United States.

Spencer returned from West Africa last week, but didn't exhibit symptoms until Thursday.

Cuomo stressed that the virus is transmitted only after a person starts feeling sick and shows symptoms, and New York officials are monitoring the four individuals that Spencer had contact with after he started showing those symptoms.

The governor said he spoke to President Barack Obama on Thursday night, as well as Ebola czar Ron Klain about the situation. New York has been well prepared for an Ebola case, Cuomo said, and he believes they have the system in place to handle the recent diagnosis.

"Now being New Yorkers, a little anxiety can keep you safe, right? And it's not a bad thing. But undue anxiety is unproductive and there's no reason for undue anxiety in this situation," he said.

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RELATED: From Guinea to the U.S.: Timeline of first Ebola patient in New York City

Republicans quickly pounced Tuesday on some controversial details from former Defense Secretary Bob Gates’ new book in which he highlights an admission from former Secretary of State Hillary Clinton that he found “dismaying” and fiercely lambasts Vice President Joe Biden.

Both are potential 2016 presidential contenders.

Gates, who led the Pentagon under two presidents from 2006 to 2011, also offered scathing critiques of President Barack Obama and Congress in the memoir, “Duty: Memoirs of a Secretary at War,” which is set to hit bookshelves next week.

According to longtime Washington Post reporter Bob Woodward, who reviewed the book, Gates said Clinton told Obama that she opposed the 2007 troop surge in Iraq for political reasons, as she was running against Obama in the Iowa presidential caucuses at the time.

“The president conceded vaguely that opposition to the Iraq surge had been political,” Gates writes. “To hear the two of them making these admissions, and in front of me, was as surprising as it was dismaying.”

In early 2007, Washington was split on whether to increase the number of troops in Iraq or to start bringing them home. Clinton was among Senate Democrats, including Biden and Obama, who opposed boosting troop levels.

“I am not in favor of sending more troops to continue doing what our young men and women have been told to do, with the government of Iraq pulling the rug out from under them when they actually go after some of the bad guys. I am not in favor of doing that unless it’s part of a larger plan,” she said in December 2006 on NBC’s “Today.”

“Everyone knows there is no military solution to the difficulties we face in Iraq,” she continued, saying there needed to be a broader plan that “includes resolving some of the political issues.”

According to CNN/ORC International polling in March 2007, 83% of Democrats opposed President George W. Bush’s plan to send about 20,000 more U.S. troops to Iraq.

For Republicans eager to get a head start on defining Clinton in anticipation of her possible 2016 presidential run, Gates’ book became quick fodder for negative attacks, even though Gates also complimented her in his memoir.

America Rising PAC, an independent Republican group, e-mailed reporters Tuesday afternoon, claiming her admission as quoted in Gates’ book “is sure to undermine her attempt to position herself as ‘serious’ on foreign policy issues ahead of a likely 2016 run.”

The Republican National Committee soon followed with its own e-mail containing a satirical question: “We’re hearing Hillary Clinton made a decision based on politics. Which one of her Super PACs will respond?”

“Hillary Clinton has a history of making decisions based on politics instead of principle,” RNC spokeswoman Kirsten Kukowski said in a separate comment. “It will be interesting to see how she addresses this with voters who have a long memory of the Clinton ways.”

Garrett Marquis, a spokesman for another anti-Clinton group, Stop Hillary PAC, argued the book excerpt proved Clinton is “disingenuous and deceitful.”

"She will do anything, including mislead the country, by putting her political ambitions ahead of the safety of Americans at home and abroad,” he said.

A source close to Gates said the former defense secretary is aware that the line about Clinton opposing the surge for political reasons could hurt her, but he was so stunned to hear her administration–and a less blunt admission from Obama–he felt obligated to print it.

The source said Gates actually has a lot of respect for Clinton, and in his book, he otherwise praised Clinton in a way that “might be used in a political endorsement,” Woodward wrote in his review.

Gates wrote: “I found her smart, idealistic but pragmatic, tough-minded, indefatigable, funny, a very valuable colleague, and a superb representative of the United States all over the world.”

And at Gates’ farewell ceremony in 2011, he had high praise for Clinton, saying she’s become a cherished colleague and a good friend.

David Brock, founder of Correct The Record, a project that frequently defends Clinton, pointed out Gates’ admiration for Clinton in the book.

“Gates’s trust in her seems to be epitomized by the high praise he reserved for her,” Brock said.

DNC Communications Director Mo Elleithee also weighed in.

"The President, the Vice President, Secretary Clinton all took office on a promise to end the war in Iraq and defeat al Qaeda so that we could end the war in Afghanistan. That’s what they’ve done," he said, adding "that’s what people will remember.”

Gates was not as complimentary about the Vice President, however.

While Gates calls Biden “a man of integrity,” he writes, “I think he has been wrong on nearly every major foreign policy and national security issue over the past four decades.”

Biden was tapped to be Obama’s running mate in 2008 largely because of his foreign policy experience. Biden was serving as chairman of the Senate Foreign Relations Committee at the time and had been in the Senate for six terms.

According to Woodward’s review, Gates expresses “outright contempt” for the Vice President and “Biden is accused of ‘poisoning the well’ against the military leadership.”

Gates named a specific example of what he considered Biden’s poor judgment in an opinion piece for the Wall Street Journal on Tuesday. He said Biden preferred a “strategy of reducing our presence in Afghanistan to rely on counterterrorist strikes from afar.”

Gates said such “’Whac-A-Mole’ hits on Taliban leaders weren't a long-term strategy.”

National Security Council spokeswoman Caitlin Hayden defended Biden in response to the book.

“The President disagrees with Secretary Gates’ assessment – from his leadership on the Balkans in the Senate, to his efforts to end the war in Iraq, Joe Biden has been one of the leading statesmen of his time, and has helped advance America’s leadership in the world. President Obama relies on his good counsel every day,” she said.

Asked about Gates’ opinion of Biden, Sen. John McCain told CNN’s Wolf Blitzer, host of The Situation Room, that he has the “greatest affection” for Biden … and he’s one of the finest men that I’ve known.”

“But he has been wrong on a lot of these issues, there’s very little doubt about that, going back to Desert Storm,” the Arizona Republican said.

McCain was pressed on whether it’s fair to say Biden has been wrong on every issue over the past four decades.

“I don’t want to recount them,” McCain said, laughing. “But he has been wrong on a number of occasions, and he was one of the factors in the whole removal of all of our troops from Iraq.”