Why would Vladimir Putin want to leak the DNC emails?

Why would Russian President Vladimir Putin want to help Donald Trump win the White House?

That's the accusation from Democrats this week, after embarrassing internal Democratic National Committee emails appeared on Wikileaks on the eve of the party's convention in Philadelphia.

The emails were lifted earlier this year in a hacking breach that security experts have linked to Russian espionage groups.

As part of their pushback against the emails' damning details, many Democrats accuse Putin of trying to help Trump's campaign. They point to mutually admiring comments between the two men, as well as Trump policy proposals that many experts say would weaken NATO and cause the United States to retreat from the world stage.

"Experts are now saying that the Russians are releasing these emails for the purpose of actually helping Donald Trump," Hillary Clinton's campaign manager, Robby Mook, told CNN on Sunday.

"That foreign actors may be trying to influence our election -- let alone a powerful adversary like Russia -- should concern all Americans of any party," said ranking House Intelligence Committee Democrat Adam Schiff on Monday.

Trump made light of the accusations on Twitter.

When asked about Russia's role in releasing the DNC emails and about any Trump ties to the Kremlin, Trump campaign chairman Paul Manafort told ABC's This Week that the accusations were "obfuscation on the part of the Clinton campaign" and that there are no ties between Trump and the Putin regime.

Still, Russia is the prime suspect behind the DNC hack. The security firm the party brought in last month to deal with the data breach immediately pointed fingers toward what it called "Russian espionage groups."

"If [it's a coincidence] it's a really great coincidence," said Russia expert Fiona Hill, who directs the Center on the United States and Europe at the Brookings Institution. "The Russians have a word -- ne sluchaino. It means, not accidental. Not by chance."

Hill said the Russian hackers may not be taking orders directly from Putin, but that they are clearly working with Russian foreign policy interests in mind.

"They don't have to be run directly by the Kremlin. They can just be encouraged," Hill said. "They [Russian security services] are very good at knowing how to play our media. We are making this email leak into a huge story, as they knew we would."

On a personal level, Trump said last fall that he and Putin "would probably get along ... very well." He has repeatedly praised Putin's strength, particularly when it comes to military intervention in Syria.

"He's running his country, and at least he's a leader, you know unlike what we have in this country," Trump told MSNBC in December.

During his annual end-of-year marathon news conference in December, Putin returned the compliment, calling Trump "a bright personality, a talented person, no doubt."

"He says that he wants to move to a different level of relations, to a closer, deeper one, with Russia," Putin said. "How can we not welcome that?"

And several advisers in Trump's orbit have close ties to Russia and Russian interests. Retired Lt. Gen. Michael Flynn, who advises Trump on foreign policy, raised eyebrows in Washington by sitting at a table with Putin during a gala for the state-run English language news channel Russia Today last year. And Trump's top adviser, Manafort, has done political consulting work for Ukrainian politicians viewed as allies to Russia.

More consequential for Moscow: Trump's repeated skepticism about the value and strength of the NATO alliance, which formed the pillar of Western Europe and North America's opposition to the Soviet Union over the past half century.

A central tenet of the North Atlantic treaty is that member states view an attack against one of them as an attack against the entire alliance. But in an interview with the New York Times last week, Trump said he didn't necessarily view NATO that way.

Asked about Russia's threatening activities, which have unnerved the small Baltic States that are among the more recent entrants into NATO, Trump said that if Russia attacked them, he would decide whether to come to their aid only after reviewing if those nations have "fulfilled their obligations to us."

"If they fulfill their obligations to us," he added, "the answer is yes."

Trump has repeatedly criticized other NATO countries for not "paying their fair share."

"We pay so much disproportionately more for NATO," Trump told a Wisconsin talk radio show in March. "We are getting ripped off by every country in NATO, where they pay virtually nothing, most of them. And we're paying the majority of the costs."

A Washington Post fact-check dove into NATO's complicated funding formula. The United States does pay more than any other country in the alliance. NATO rules require every country to spend 2 percent of its GDP on defense, but most alliance members regularly fall short of that guideline.

American politicians have long groused about that spending gap; President Obama regularly chided former British Prime Minister David Cameron about not meeting that goal. But no president or presidential candidate has ever openly questioned the fundamental structure of the alliance like Trump has.

The NATO skepticism plays into a much broader isolationist view that Trump has taken during his campaign, a view that would undoubtedly benefit internationally proactive countries like Russia, if it were carried out by a President Trump.

"The most important difference between our plan and that of our opponents is that our plan will put America first," Trump said Thursday night during his convention speech. "Americanism, not globalism, will be our credo."

The timing of the Wikileaks dump, which ripped open the scab of Democratic disunity on the eve of the party's convention, raises the question of whether the Russian hackers have any other embarrassing material that could affect the American electorate.

"This is the dream situation for the Kremlin," said Hill, who previously worked as the National Intelligence Council's top Russia expert. "To have this very dirty, incredibly contested election playing out in the United States. There has been so much commentary in the U.S. about their flawed political system. There must be a great deal of schadenfreude there today."

NPR's Mary Louise Kelly contributed to this report