President Trump came into office signaling a desire to improve relations with Moscow, pledging on the campaign trail to “get along great” with President Vladi­mir Putin and win his respect.

With the conclusion of special counsel Robert S. Mueller III’s investigation, the president has won more freedom to pursue that goal. But experts say the sand has shifted significantly in Washington since the inauguration, with limitations imposed by Congress and policies implemented by Trump’s own administration reducing the likelihood of any substantive rapprochement with Russia in the near term.

In the more than two years since Trump entered the White House, the United States has grown more entrenched in its opposition to Moscow, despite the president’s reluctance to acknowledge Russian threats. Congress has passed broad restrictions on Russia with votes that would override a presidential veto. Trump’s administration has turned the screws on the Kremlin through military policy, decisions on nuclear arms and pushback against Russia in Venezuela. Signs of a new arms race have emerged. 

The result is hardened bipartisan consensus in Washington against any effort to warm relations with Moscow — a barrier that would prove difficult for Trump to surmount at home, in addition to the challenges he would face striking deals with Putin on a range of disputes overseas. 

“There’s so much water that has passed under the bridge since the inauguration in the bilateral relationship that he’s no longer starting from a blank slate,” said Sam Charap, a Russia expert at the Rand Corp.

In 2017, out of concern about the president’s reluctance to call out Russia on election interference, Congress passed a raft of sanctions on Russia known as CAATSA, which limit the president’s ability to modify or lift punitive measures without congressional approval. The Trump administration also imposed sanctions on Russia for its alleged poisoning of a former Russian spy in Britain and is still dealing with the fallout from an incident in the Kerch Strait last November in which a Russian coast guard ship fired on three Ukrainian naval vessels and captured its sailors.

CAATSA alone is a challenge for Trump. “When he came into office, he wanted to lift sanctions,” said Angela Stent, a Russia expert in the George W. Bush administration and author of the new book “Putin’s World.” “Now that’s gone; sanctions are congressionally mandated. He can’t use that as a lever with the Russians.”

In Russia, some expressed hope that the end of the Mueller investigation would bring a moment of renewal for relations with the United States. 

An opportunity for a “reset” may have finally arrived, Konstantin Kosachyov, chairman of the foreign affairs committee in the upper house of the Russian parliament, said in a Facebook post Monday. Russia must seize the moment to deal with Trump, Kosachyov wrote, now that the cloud of collusion allegations no longer looms over the White House. Nuclear arms control, he said, should be at the top of the agenda. 

“The effect of the Mueller report puts all the aces in the Trump team’s hands,” Kosachyov said. “There’s a chance to reset much in our relationship, but the question is whether Trump will risk it.” 

After the 2016 election, Russian officials had hoped Trump’s presidency could herald a chance to lift sanctions on Moscow, engage in new arms-control talks and win U.S. support for Russian foreign policy priorities in Ukraine and beyond. Instead, in Moscow’s view, those hopes were dashed by a U.S. foreign policy establishment that used allegations of Russian election interference to undermine Trump’s plans to improve U.S.-Russia ties.

Fyodor Lukyanov, a prominent Moscow political analyst, said in an interview that officials needed to keep expectations low. Even though Trump has often paid lip service to the need to improve relations with Russia, Lukyanov said, his actions have shown that he has little interest in doing so. 

“I’m personally afraid that, indeed, there might be some illusions now that something new will happen,” said Lukyanov, chairman of Russia’s Council for Foreign and Defense Policy, a research group. He predicted new efforts by the Kremlin to build ties with Trump and, perhaps, to hold a summit. “But from my point of view,” Lukyanov added, “it’s completely hopeless.”

Since Trump won the presidency in late 2016, the mood in Washington’s policymaking circles regarding Russia has been one of compensatory overdrive, with officials inside and outside the administration pushing a hard line in part to counter Trump’s perceived nonchalance about Russian threats.   

Mueller’s report, according to a summary submitted to lawmakers by Attorney General William P. Barr, “did not establish that members of the Trump Campaign conspired or coordinated with the Russian government in its election interference activities.” 

But the special counsel’s investigation did confirm that two Russian efforts sought to influence the outcome of the 2016 election — one by spreading disinformation on social media and the other by hacking and releasing Democratic Party and Clinton campaign emails. Mueller brought criminal charges against Russian citizens and military officers for those activities.

Trump, however, has cast doubt on those conclusions. During a summit with Putin in Helsinki last year, he suggested he didn’t believe U.S. intelligence services and said he found the Russian leader’s denial convincing. If Trump doesn’t show acknowledgment of Russia’s activities, experts say, he will continue to face opposition and skepticism in Washington about moves regarding Russia.

“The operative phrase in Washington is ‘malign influence,’ ” said Thomas E. Graham, managing director at Kissinger Associates and a former senior director for Russia on the White House National Security Council under George W. Bush. “Congress certainly believes that Russia exercises malign influence. The administration minus the president believes Russia is exercising malign influence. But the president doesn’t speak in a way that suggests he recognizes that Russia is exercising malign influence.”

Graham said that “there is not a lot of trust in the president’s instincts on Russia,” and added that the Mueller report’s findings weren’t going to change that.

In Russia, backers of Putin seized on Mueller’s report as evidence that the notion of Russian interference in the 2016 election writ large was untrue, although the investigation concluded the opposite.

Asked on his daily conference call with journalists Monday about the conclusion of Mueller’s investigation, Kremlin spokesman Dmitry Peskov referred to “a Chinese philosopher who said, ‘It is hard to find a black cat in a dark room, especially if it is not there.’ ”

“Centuries have passed, but unfortunately there has been no understanding of this on the other side of the ocean,” Peskov said. 

Alexey Pushkov, a foreign affairs specialist in the upper house of parliament, described Mueller’s findings as exonerating Trump in the face of a “virtual conspiracy” of U.S. news media and Democrats that was aimed at demonizing Russia. 

“The agents of conspiracy theory have been discredited,” the Russian lawmaker posted on Twitter. “From now on, only an idiot can believe them.” 

A post by the state-controlled Russian television network RT on the instant messaging platform Telegram said the Pulitzer Prize won by the New York Times and The Washington Post in 2018 for reporting on Russian election interference was “a Pulitzer for fake news.” Hours earlier, Donald Trump Jr., the president’s son, had referred on Twitter to that prize as the “#fakenews awards.” 

Given the various constraints on the president, the biggest changes to U.S.-Russia policy post-Mueller report may be incremental in areas related to bilateral meetings, and geopolitical flash points such as Syria and Afghanistan.

Ever since the Kerch Strait incident, for instance, the United States has conditioned the scheduling of high-level White House meetings on Russia’s return of Ukraine’s sailors. Charap said one gesture Trump could make is lifting those conditions and restarting meetings between national security adviser John Bolton and his counterpart, Nikolai Patrushev.

U.S. and Russian officials continue to meet at lower levels, including discussions related to securing a lasting peace agreement in Afghanistan, arms control, a political resolution in Syria, and a denuclearization agreement with North Korea. “There may be more of a push to engage on these issues, but I think these would be very incremental steps,” Stent said. “The issuance of the Mueller report is not a game changer.”

Despite the downward trajectory of U.S.-Russia relations, the president has repeatedly demonstrated a personal interest in improving ties. And although his Cabinet is deeply skeptical, some of the president’s informal ­advisers have urged him to take incremental steps toward rapprochement. Sen. Rand Paul (R-Ky.), a libertarian who golfs with the president and speaks with him on the phone, has pushed Trump to improve relations with Moscow.

Trump has expressed interest in negotiating on an arms control deal with Russia dating to the 1980s, and could revive those efforts in the run-up to the 2021 expiration of the New START accord, which limits strategic nuclear arms. The Trump administration has begun holding meetings looking at whether to extend that agreement, and the president has yet to make a decision on the matter.

Troianovski reported from Moscow.