Donald Trump faced pushback Thursday from current and former NATO officials after suggesting that if elected he might not protect certain members of the 28-nation coalition against Russian aggression.
NATO Secretary General Jens Stoltenberg, while saying he would not "interfere" with the U.S. election, responded by urging unity among NATO countries.
“Solidarity among allies is a key value for NATO,” Stoltenberg said in a statement. “We defend one another. … The United States has always stood by its European allies.”
He added, "Two world wars have shown that peace in Europe is also important for the security of the United States."
James Stavridis, retired four-star Navy admiral who served as the 16th supreme allied commander of NATO, also tweeted: "Trump on NATO: deeply dangerous will dismay our closest Allies but great cheer in Kremlin: I can hear Vladimir Putin chortling from here."
Stoltenberg spoke in response to Trump suggesting Wednesday in a New York Times interview that he would decide whether to protect Baltic republics against Russian aggression based on whether they have “fulfilled their obligations” to the United States and other NATO countries.
Democrats also piled on. “Harry Truman and Ronald Reagan would be ashamed,” Democratic National Committee Chairwoman Debbie Wasserman Schultz said Thursday in Cleveland, just blocks from where Trump is scheduled to accept the nomination at the Republican National Convention.
NATO, or the North Atlantic Treaty Organization, is a military alliance of European and North American democracies created after World War II to strengthen international cooperation as a counter-balance to the rise of the Soviet Union.
In 2014, NATO created a rapid-reaction force to protect its most vulnerable members against a confrontation with Russia.
Trump’s remarks about the United States’ obligations under NATO to others in the coalition are in line with previous comments questioning the United States' global role.
The billionaire businessman and first-time candidate has previously suggested the U.S. pull out of NATO, considering the country pays more than its share while also having to underwrite global security.
White House Press Secretary Josh Earnest said the “cornerstone of [the NATO] alliance is the pledge that all of the allies have made to mutual self-defense.”
Last week, President Obama pledged unwavering commitment to defending Europe, adding that "in good times and in bad, Europe can count on the United States."
The campaign for presumptive Democratic presidential nominee Hillary Clinton was among the first to pounce on Trump's statements.
"The president is supposed to be the leader of the free world. Donald Trump apparently doesn't even believe in the free world," said Clinton senior policy adviser Jake Sullivan shortly after the interview was published.
Trump's running mate, Indiana Gov. Mike Pence, was on the defensive early Thursday, telling Fox News that he is confident Trump would stand by America's NATO allies, but insisted that those countries "must pay their fair share."
Fox News’ Lucas Tomlinson and The Associated Press contributed to this report.