'Who do you believe?'

It was a simple question, asked of President Trump by a seasoned reporter, but it sent a jolt through the assembled media at the July 16 press conference held at an ornate palace in Helsinki. Vladimir Putin had just denied again that Russia interfered in the 2016 U.S. presidential election. America's Justice Department, intelligence community and both chambers of Congress have concluded, definitively, that the Kremlin had done it. Who did Trump trust more?

This was the moment for the President to deliver a forceful rebuke to America's long-standing adversary. Instead, Trump replied: "I have confidence in both parties," he said. "I have great confidence in my intelligence people, but I will tell you that President Putin was extremely strong and powerful in his denial today."

The founders of the United States gave future Presidents just one grave set of instructions, enshrined in Article II, Section 1 of the Constitution. Before assuming the office, the President-elect must swear to "preserve, protect and defend" the Constitution and "faithfully" execute the duties of the office. Russia's 2016 attack had been designed, first and foremost, to undermine faith in American democracy at home and abroad. There could hardly be a more direct call for the President to be true to that oath. On the dais in Helsinki, Trump wasn't up to the task.

The government he leads had tried to prepare him. Days before the summit, Trump had been briefed in person by Deputy Attorney General Rod Rosenstein on the details of an indictment against 12 officers of Russia's military intelligence services who had executed key elements of the 2016 attack. The charges, compiled by special counsel Robert Mueller and released to the public on July 13, were meticulous in their evidence, damning in their conclusions and based at least in part on deep penetration of Russia's intelligence services by their American counterparts. Even the Russians seemed stunned, not so much by the revelations themselves as by Trump's unwillingness to stand by them. "Whenever a head of state does not trust his own intelligence agencies," retired KGB general Vladimir Rubanov tells TIME, "that's a big problem for the country where that happens."

It was only the latest offense. The U.S. recently expelled 60 Russian spies in retaliation for Moscow's alleged nerve-agent attack against a former Russian spy and his daughter in England . U.S. Homeland Security officials and members of Congress are scrambling to defend the 2018 midterm elections against what they report are continued Russian efforts to undermine American democracy and its citizens' faith in the ballot box. And around the world, the U.S. and Russia are in a tense standoff, from the airspace near Alaska, where Russian bombers regularly test American readiness to counter an attack, to the borders of Ukraine, to the battlefields of Syria, where Russian mercenaries attacked a U.S. special-forces base last February.

In addition to calling Putin's denials "powerful," Trump praised the Russian as a "good competitor" and called America itself "foolish" for allowing the relationship between the two countries to deteriorate. He welcomed the prospect of working with Russia in Syria and hailed Putin's offer to cooperate with the Mueller probe in exchange for helping to investigate the British investor Bill Browder as "an incredible offer."

The reaction was immediate, and as profound as what had just occurred. Trump's infidelity to the expectations of his office as Commander in Chief left foreign-policy veterans stunned. "That press conference was the single most embarrassing performance by an American President on the world stage that I've ever seen," said William Burns, president of the Carnegie Endowment for International Peace, who served as an aide to Republicans such as James Baker and Condoleezza Rice before becoming Deputy Secretary of State under Barack Obama. Even Republicans began to publicly entertain the possibility that Trump had been compromised. "That's how a press conference sounds when an Asset stands next to his Handler," tweeted former Republican National Committee chairman Michael Steele.

The prostration of a U.S. President felt all the more significant because of what had come immediately before: another repudiation of a world order led by America. The venue this time was a meeting of NATO, the military alliance that has guaranteed global security since World War II. Trump dismissed it during his campaign as "obsolete" and has vacillated about U.S. commitments while in office. Key U.S. partners are now reconsidering their need to defend themselves. "We can no longer completely rely on the White House," Germany's Foreign Minister Heiko Maas said after Trump's tour of the Continent. "Historians," wrote Belgium's former Prime Minister Guy Verhofstadt, "will view this visit as the moment the post-1945 world order was upended."

Some Trump allies tried to minimize the damage by saying Trump's behavior reflected only the President's insecurity, rather than an intentional breach of faith with the country he leads and its longtime partners. In this view, Trump was driven by a reflexive defense of his own political legitimacy and his victory in 2016, not a deeper alliance with Putin. But imbedded in that explanation was another description of the core problem: Trump justified his break with traditional allies--countries that sent troops to die in Afghanistan and Iraq-- as a manifestation of his "America first" approach to foreign policy. His performance in Helsinki and the days after was more akin to "Me first." The President shrugged off subjugation of the most basic needs of U.S. democracy--free and fair elections--by a hostile power. When he stood next to a smirking Putin and sided with America's most dangerous enemy against the hundreds of thousands of men and women in the U.S. national-security apparatus, he exposed just how deep and perilous this can be. Any other President might have found reason to avoid Putin altogether. Aside from the global problems he has aggravated, from Syria to Ukraine, the Russian has been nothing but trouble for Trump personally, casting a shadow over his election with meddling that in turn prompted the formidable special-counsel investigation that clearly preoccupies the President. White House aides were worried that the meeting was an unnecessary risk and that insufficient preparations had been made to define the agenda and goals. On top of that, there was no clear plan for how Trump should respond to the mounting public evidence about the Russian operation against the 2016 election. Mueller's 29-page indictment outlines a sophisticated conspiracy by Russian military officers, targeting over 300 individuals affiliated with Hillary Clinton's campaign and the Democratic Party. The Russians hacked into their computers, stole documents and orchestrated the release of those stolen files "to interfere with the 2016 presidential election," according to the indictment.

Mueller's team compiled granular details about the operation, including the addresses of buildings used by Russian intelligence services. The indictment cites a building called the "Tower" on Kirova Street in Moscow, where the Russian military intelligence service, the GRU, facilitated the release of stolen documents and publicized anti-Clinton content on fake social-media accounts. It also names specific accounts the hackers used, the dates and locations from which they launched attacks and even how long certain attacks lasted.

That U.S. intelligence was willing to show how deeply it had penetrated their Russian adversaries' computer systems is a testament to how important America's spies believe it is to hold Russia accountable. On June 20, 2016, for example, Russian spies allegedly spent more than seven hours trying to connect to the Democratic Congressional Campaign Committee network, U.S. authorities found. On April 15, 2016, the indictment claims, the conspirators searched a hacked DCCC computer for specific search terms, including "hillary," "cruz" and "trump," and copied folders from the computer, including one called "Benghazi Investigations."

Once they had stolen files, the hackers created online personas, including the infamous Guccifer 2.0, to release the information through organizations and individuals. On June 27, 2016, the indictment alleges, Guccifer 2.0 offered to send a U.S. reporter stolen emails from "Hillary Clinton's staff." Mueller's team found that the Russians had primarily used Bitcoin to pay for their hacking activity. The indictment even lays out ways the Russian hackers tried to cover their tracks, noting that on May 13, 2016, they deleted logs from a Democratic National Committee computer they had infiltrated.

America's confrontation with Russia is not limited to the escalating spy wars. U.S. and Russian forces operate in close proximity at several flash points in the Middle East and Eastern Europe by flying warplanes, sailing battleships and training proxy forces on the ground. The U.S. has invested millions of dollars in rebuilding long-forgotten outposts to restart submarine surveillance because of a surge in Russian submarine operations, and American fighter jets routinely intercept long-range Russian bombers off the western coast of Alaska.

Nowhere is the U.S.-Russia relationship more perilous than in Syria, where the two nations are on opposite sides of that country's bloody civil war. American warplanes have carried out thousands of airstrikes against ISIS militants, while Russian bombers conduct strikes to support the government of President Bashar Assad. Both nations also have hundreds of troops and military contractors on the ground. On Feb. 7, scores of Russian mercenaries were killed after crossing the Euphrates River in a four-hour-long barrage laid down by American warplanes.

All this makes Trump's posture toward Putin even more baffling, especially as he undermines the decades-long transatlantic alliance that has long galled the Russian. The President's decisions to leave the 2015 Iran nuclear deal and back out of the Paris Agreement have eroded European leaders' faith in America's ability to live up to its international obligations. And Trump's reluctance to fully embrace the U.S.'s long-standing commitment to protect members of NATO--the organization's central tenet--has raised more alarms.

During Trump's first visit to NATO headquarters in Brussels last year, he cut from his speech a mention of Article 5--the section of the NATO treaty about mutual defense--only to affirm it later under pressure. He signed the NATO communiqué during his most recent trip, but in an interview with Fox News' Tucker Carlson that aired on July 17, Trump hesitated to say he would want American troops to come to the defense of Montenegro, the Balkan country that joined NATO last year after a Russian-linked coup attempt failed to derail its accession to the alliance. In the view of Toomas Hendrik Ilves, who served as the President of Estonia from 2006 to 2016, the changes Trump has brought to Europe are permanent. "This idea that we will always have the United States is now gone," Ilves tells TIME.

Perhaps the most pressing challenge for the U.S., however, is the security of its cybersystems. The same day that Mueller's indictments were announced, Director of National Intelligence Dan Coats said that when it comes to cyberattacks against America, Russia is the "most aggressive foreign actor, no question." Many of those efforts, Coats said, continue to be designed "to undermine our democracy." Homeland Security Secretary Kirstjen Nielsen doesn't see Russia hitting the 2018 elections with the same "scale or scope" that it did in 2016, but she acknowledged on July 14 that U.S. intelligence shows "persistent Russian efforts using social media, sympathetic spokespeople, and other fronts to sow discord and divisiveness amongst the American people."

Yet for some reason Trump still isn't buying it. Asked at a July 18 Cabinet meeting whether Russia was still targeting U.S. elections, Trump appeared to shake his head and say, "No." For the second time in as many days, the White House was obliged to reinterpret his remarks.

But attempts at damage control have done little to soften the criticism. Republican Senator John McCain called Trump's performance "disgraceful" and said "no prior President has ever abased himself more abjectly before a tyrant." The Senate Democratic leader, Chuck Schumer, said the summit raised the question of whether Putin had some kind of damning information on Trump. "There seems to be no rational explanation for President Trump's behaviors," said Schumer, "so millions of Americans are left wondering if Putin indeed has something over the President."

A year and a half into his presidency, Trump's puzzling affinity for Putin has yet to be explained. Trump is bruised by the idea that Russian election meddling taints his victory, those close to him say, and can't concede the fact that Russia did try to interfere in the election, regardless of whether it impacted the outcome. He views this problem entirely through a political lens, these people say, unable or unwilling to differentiate between the question of whether his campaign colluded with Russia--which he denies--and the question of whether Russia attempted to influence the election. "Trump got hung up on his own personal issues" about the election, says Michael Allen, who served on President George W. Bush's National Security Council.

Whatever the President's rationale, his equivocation in Helsinki paralleled on the international stage his controversial statements in defense of white nationalists in August 2017. As with the aftermath of that controversy, some Republicans rebuked the President. Many are loath to rein him in because they fear Trump's popularity with GOP voters, yet even typically cautious Republicans viewed the Helsinki conference as crossing a line. Senate GOP leadership gave its members the green light to criticize the President. A bipartisan bill that would impose severe sanctions if Russia is caught meddling in 2018 or other future elections had stalled in the Senate. Helsinki has breathed fresh life into the effort. Republican Senate aides said it could pass the chamber with even a veto-proof majority.

Away from the political scrum, other U.S. officials are stepping up their defense against Russian influence operations. The Department of Justice's national-security division has taken over the prosecution of the 12 Russian GRU hackers. Bookending the spectacle of the summit in Helsinki, the DOJ on July 16 released a new set of charges against Maria Butina, a Russian national who allegedly infiltrated the NRA, the National Prayer Breakfast and other GOP-friendly organizations during and after the 2016 campaign in an attempt to influence them. (Butina pleaded not guilty on July 18.)

The continuing efforts by the U.S. Department of Justice and the U.S. intelligence community are a useful reminder to Trump, Putin and the rest of the world. Whatever the fallout from the Helsinki summit, no one man ultimately controls the enforcement of America's laws or the defense of its national security. And nothing Trump says or does will change that.

With reporting by Tessa Berenson and Simon Shuster/Helsinki; Philip Elliot and W.J. Hennigan/Washington