WARSAW, Poland — President Trump promised voters that he would strike “a great deal” with Russia and its autocratic president, Vladimir Putin. He has repeatedly labeled an investigation of Russian meddling in the U.S. elections as “a hoax,” and he even bragged to Russian officials about firing the FBI director leading the probe.

Now nearly six months into his presidency, Trump is set to finally meet Putin at a summit this week in Hamburg after a stop here in Warsaw – severely constrained and facing few good options that would leave him politically unscathed.

If Trump attempts to loosen sanctions against Russia for its involvement in the conflict in eastern Ukraine or its interference in the 2016 U.S. election, Congress could defy him by pursuing even stronger penalties. And if he offers platitudes for Putin without addressing Russia’s election meddling, it will renew questions about whether Trump accepts the findings of his own intelligence officials that Russia intended to disrupt the democratic process on his behalf.

“The president is boxed in,” said Nicholas Burns, a former U.S. ambassador to NATO under President George W. Bush. “Why would you give Putin any kind of concession at the first meeting? What has he done to deserve that?”

He added, “If you try to curry favor offer concessions, pull back on the pressure, he’ll take advantage. He’ll see weakness in a vacuum.”

Already, Moscow is clamoring for the Trump administration to return two Russian compounds in the United States that were seized by the Obama administration in retaliation for Russian meddling. And the Trump administration signaled in May that it would be open to returning the properties.

SENATE FAVORS TOUGH SANCTIONS

Yet in the Senate, there is rare near-unanimity in favor of tough sanctions against Russia. Last month, the Senate voted 97 to 2 for a bill that would put new sanctions in place for Russia’s election meddling and would constrain Trump’s ability to lift existing penalties. The White House was forced to step up its lobbying of Republicans in the House to slow the progress of a similar measure.

Among the foreign policy experts who support Trump’s push for improved relations with Russia, there is growing frustration that the current political climate and Trump’s actions have made it all but impossible.

“It has been extraordinarily difficult for Trump, even if he had the means to do so, to do what is in the vital national interest, that is, improve relations with Russia,” said Jack Matlock, a former ambassador to the Soviet Union under president Ronald Reagan who favors improving relations with Russia. “Treating them as if they are enemies is absolutely absurd, and yet it permeates much of the attitude in Congress.”

The Trump administration, meanwhile, has been moving on multiple fronts to soften the U.S. stance on Russia.

Trump wants Russia’s cooperation in a number of simmering conflicts, including the fight against the Islamic State group in Syria and Russia’s use of North Korean laborers whose pay goes directly to the regime in Pyongyang, despite its nuclear weapons program.

Secretary of State Rex Tillerson has tried to ward off Congress from imposing more sanctions on Russia for its involvement in Ukraine, saying that getting tough now could hamper cooperation on other issues. Tillerson also said last month that the administration is not necessarily wedded to the Minsk agreement to end the fighting in Ukraine. That’s a shift in position since March, when he told a meeting of NATO foreign ministers that the United States would not ease sanctions until Russia meets its Minsk commitments.

ECHOES OF COLD WAR HOSTILITY

“The president asked me to begin a re-engagement process with Russia to see if we can first stabilize that relationship so it does not deteriorate further, and then can we identify areas of mutual interest where perhaps we can begin to rebuild some level of trust and some level of confidence that there are areas where we can work together,” Tillerson said during a visit to New Zealand in June. “The president has been clear to me: ‘Do not let what’s happening over here in the political realm prevent you from the work you need to do in this relationship.’ ”

Despite Trump’s consistent overtures to Putin, however, U.S.-Russia relations have not improved since he took office.

Putin has strongly denied any interference in the 2016 election and has accused U.S. politicians of Cold War-era hysteria. Meanwhile, Russia’s continued support for Syrian President Bashar al-Assad’s massacre of his own citizens in the country’s civil war has further engendered distrust among U.S. political leaders.

Paul Saunders, who directs the U.S.-Russia program at the Center for the National Interest, said the level of mutual distrust and hostility is as bad as it was during the height of the Cold War.

“Without progress on Ukraine, I don’t see how one would ease sanctions,” he said. “And it’s not like Russia is going to send special forces to Damascus to arrest Assad and deliver him to The Hague or to President Trump.”

Trump, who has been criticized for his overly warm posture toward Putin, has not indicated how he will approach the meeting this week.

In recent months, Trump has done little to hide his frustration that his effort to pivot toward Russia has been hampered by congressional and FBI investigations, which he views as a “witch hunt” being carried out by his political enemies.

In light of the continued pressure from both parties, White House aides have sought to play down expectations for this first engagement between the two.