Behind the tough talk on Russia expected from President Obama and other leaders gathering in Germany this weekend is a stark reality.

None of the world powers believes the economic and diplomatic punishments levied on Russia for its alleged aggression in Ukraine are changing President Vladimir Putin's calculus, yet there are no plans to shift strategies.

At most, leaders hope to emerge from two days of talks in the Bavarian Alps with an agreement to keep U.S. and European Union sanctions against Russia in place, and perhaps a pledge to enact deeper economic penalties if the crisis escalates. While there is little expectation that a show of unity will lead to a quick resolution in Ukraine, officials hope it will at least give Putin pause if he is considering ratcheting up Russia's moves.

A fresh outbreak of violence between government troops and pro-Russian separatists in eastern Ukraine is threatening to derail an already tenuous cease-fire.

The fact that sanctions have not altered Putin's military posture is "a sign of how heedless the Russian government seems to be about the long-term welfare of its own people that it has not yet resulted in a change, in a reversal at least of course, which is what we want out of Russia," Defense Secretary Ash Carter told reporters after a Friday meeting in Germany with American military and diplomatic leaders.

The Group of Seven summit marks the second year in a row that leaders from the United States, Canada, Britain, France, Germany, Italy and Japan will assemble without Putin. After Russia annexed territory from Ukraine last year, the world powers kicked Russia out of what had been called the Group of Eight, a move aimed at isolating Putin and signaling the West's united opposition to his provocative actions.

Yet Putin remains a major player on pressing issues.

Russia is a partner of the U.S. and other nations in the nuclear talks with Iran, an Obama priority. Putin is a linchpin in any discussions on resolving the civil war in Syria, given Russia's status as President Bashar Assad's biggest benefactor.

Republicans have accused Obama of putting his interest in the Iran nuclear talks above supporting Ukraine. GOP White House hopeful Jeb Bush is set to arrive in Europe just as Obama departs, with stops in Germany, Poland and Estonia. Bush is expected to pledge broader U.S. backing for the region if elected president.

White House officials defend the engagement with Russia on Iran and other matters, and say the U.S. can work with Moscow on issues of mutual interest while also confronting Putin over Ukraine.

But experts say Secretary of State John Kerry's meetings with Putin in Russia last month raised questions in Europe about whether Washington might be pursuing a new policy toward the Kremlin. Kerry's trip was the first time a senior U.S. official has traveled to Russia since Moscow annexed the Crimean Peninsula from Ukraine.

"It created this cloud of controversy around what is the U.S. strategy: Why did he go?" said Julianne Smith, a former Obama White House official who is now a senior fellow at the Center for New American Security. "So I think there'll be a little bit of mopping up from that trip."

European nations are watching whether the U.S. commitment to isolating and penalizing Russia is weakening. Europe has far stronger ties to Russia than the U.S. and some leaders face pressure from the business community to ease off of penalties that have affected their finances.

Still, the European Union is expected to renew expiring sanctions later this summer.

Obama planned to leave Washington on Saturday evening after delivering remarks at the funeral service for Vice President Joe Biden's son, Beau, who died of brain cancer. Set to join the president on Air Force One for the trip to Germany were four House Democrats who support his efforts to win special authority to negotiate a Pacific Rim trade deal.

The trade debate on Capitol Hill is being closely watched by G-7 leaders. While Obama has Senate backing to seek fast-track authority of the Trans Pacific Partnership pact, he faces a steep challenge in getting his own party's support in the House. Japan and Canada are both part of TPP.

European nations are not part of the pact, but the congressional debate could affect whether Obama has the political capital left to pursue a trans-Atlantic trade deal with the EU before leaving office

After his overnight flight to Munich, Obama was to meet with German Chancellor Angela Merkel, then join other leaders for talks at Schloss Elmau, a one-time Bavarian artist retreat turned luxury spa.

Also on Obama's schedule was a meeting with British Prime Minister David Cameron, whose party is coming off an unexpectedly strong election victory. The president also planned to see Iraqi Prime Minister Haider al-Abadi, who was invited to the G-7 meeting to discuss the U.S.-led campaign against the Islamic State in his country, as well as in Syria.