WASHINGTON (Reuters) - When Donald Trump meets Vladimir Putin, he sits down with a disciplined, detail-oriented and experienced Russian leader who has played on the world stage for more than 18 years, in contrast to the U.S. president’s 18 months in office.

Former U.S. officials argue that Putin will come to the July 16 Helsinki summit armed with facts and figures, flaunting a familiar narrative of Russian grievance and probing for a way to get something from Trump for little or nothing in return.

Trump’s June 12 summit with North Korea’s Kim Jong Un - in which he agreed to halt U.S.-South Korean military exercises in return for what may prove hollow North Korean denuclearization promises - will loom large in the Russian president’s mind.

“He will have watched the Kim Jong Un summit and he will have the same appraisal: that Trump gave away a major American card without getting anything concrete back for it,” said a former senior U.S. official. “He’ll be looking for at least that kind of outcome and he will be willing to flatter and promise and manipulate to get it.”

However, Putin may also seek an outcome in which Trump can declare victory in the hopes that Russia may eventually get what it wants - legitimizing its annexation of Crimea, easing of U.S. sanctions, and concessions on arms control.

“He’ll play the long game on this, he’ll see this as an investment, as one step down the road toward an ... easing of outside pressure,” said Bill Burns, a former U.S. ambassador to Russia and deputy secretary of state involved in some of George W. Bush and Barack Obama’s summits with Putin.

“He is going to understand that playing to ego is a smart thing to do,” Burns added.

Trump, whose 2016 election campaign is being probed for possible collusion with Russia, has said repeatedly he wants to have a good relationship with Washington’s former Cold War foe, despite tensions between Russia and the West over Ukraine, Syria and alleged election meddling around the world.

A former real estate developer who sees himself as a master deal maker, Trump comes to the talks at something of a disadvantage given Putin’s KGB background and his long history of dealing with U.S. presidents, of which Trump is the fourth.

FILE PHOTO: U.S. President Donald Trump shakes hands with Russian President Vladimir Putin during the their bilateral meeting at the G20 summit in Hamburg, Germany, July 7, 2017. REUTERS/Carlos Barria/File Photo

Michael McFaul, a former U.S. ambassador to Russia under Democrat Obama, said Trump should prepare well and not simply rely on gut instinct when going up against Putin, who has a black belt in judo.

“President Trump spent most of his life not working on foreign policy. President Putin has spent most of his life working on foreign policy and national security issues,” said McFaul. “By virtue of what they’ve done with their lives, he’s behind and he needs to prepare.”

McFaul said Putin could be persuasive, armed with his arguments and lots of confidence. “His interpretations are flawed and have some empirical pieces missing,” McFaul said. “But he’s effective when he tells those stories.”

Asked how Trump was preparing for the summit, which will begin with a one-on-one meeting, a White House National Security Council spokesman said: “The president and his team will be prepared to discuss all issues in the U.S.-Russia relationship.”

While Washington has imposed economic sanctions on Russia since Trump took office, the president himself has taken a softer line toward Moscow than many of his aides, saying Russia should rejoin the Group of Eight industrial nations from which it was ejected after its March 2014 annexation of Crimea.

The forum, which includes Britain, Canada, France, Germany, Italy, Japan and the United States, is now called the Group of Seven.

Trump told leaders at the June G7 summit in Canada that Crimea is Russian because everyone who lives there speaks Russian, Buzzfeed reported, citing two diplomatic sources.

Former U.S. officials said Putin might try to sell Trump on Russia helping pressure Iran to remove its proxies from southwestern Syria but probably understood there was little chance of sanctions easing because of congressional opposition.

Recognizing that Trump’s stance on Russia is softer than that of the U.S. national security establishment, Putin may play to the American president’s desire to be seen as an iconoclastic actor who is not a prisoner of conventional wisdom.

Kremlin-backed media have cast Trump as being surrounded by advisers out to thwart his legitimate decisions. The Kremlin has made clear it is happy for the two men to initially meet one-on-one without their aides, a prospect which has alarmed some Trump critics who fear Putin will easily be able to manipulate Trump.

“You and I are unconstrained colossuses on this planet and it’s just all the small people and the haters who want to keep this relationship down,” the former official said of Putin’s likely pitch. “We can cut unique deals ... let’s go.”