THE HAGUE, Netherlands (CNN) -- For the White House, this hectic, week-long journey to Europe and Saudi Arabia was supposed to showcase President Barack Obama's leadership on the world stage.
Russian President Vladimir Putin changed that with his military intervention into Ukraine's Crimean peninsula.
Now the Nuclear Security Summit set for The Netherlands Tuesday is seemingly taking a back seat to a high-stakes confrontation with Putin.
The summit is the third such gathering of world leaders since Obama helped launched the initiative in 2009.
The U.S. President will also make his first visit with Pope Francis in Rome, a meeting to highlight the shared concern of income inequality.
At his first stop in The Netherlands with Prime Minister Mark Rutte, Obama put Putin on notice.
The United States and its allies in Europe are "united in imposing a cost on Russia for its actions so far," Obama said.
In Europe, Obama finds himself in a familiar position. His trip to the G-20 meeting last September in Saint Petersburg was dominated by questions about whether the President would take military action against Syria, Putin's strongest ally in the Middle East. At the G-20, Obama and his aides could only watch as Putin beamed with Russian pride, hosting a global economic summit that closed with a spectacular fireworks show and promoted the upcoming Olympic Games in Sochi.
Even Obama's latest trip to Mexico came with its own Putin sideshow. As unrest spread in Ukraine, Obama said he did not see the Eastern European nation as part of a larger Cold War chessboard.
But perhaps Putin did.
Obama, whose aides have repeatedly said he was elected to end wars, not start them, is seeing his soft-power, diplomacy-first default setting put to the test.
The President has said a military incursion in Ukraine is off the table, and his advisers are hesitant to even frame the crisis in Ukraine as a bad '80s flashback -- Obama in one corner, Putin in the other. It's not "Rocky IV," as Secretary of State John Kerry said.
Nor do White House officials care to publicly muse about Putin's intentions.
National Security Adviser Susan Rice said the Russian President's actions speak for themselves.
"I'm not going to get into speculating about President Putin's motives," Rice told reporters Friday.
The White House emphasis throughout the Russian occupation of Crimea has been "de-escalation."
Asked whether the United States will provide military aid to Ukraine's woefully underfunded armed forces, administration officials cautioned that such assistance could inflame tensions.
"Our focus has been and remains on the economic and diplomatic instruments at this point," Rice said. "Our interest is not in seeing the situation escalate and devolve into hot conflict."
While Democratic and Republican lawmakers are stepping up their calls to provide Ukraine with light arms and other military aid, administration officials have argued that the sanctions put in place by the United States and the European Union must be given time to take hold.
With an estimated 20,000 Russian troops on Ukraine's border, the question is whether Obama's use of soft power will deter Putin.
With little resistance, the Russian president could easily move into Eastern Ukraine even as Obama seeks to isolate Moscow in meetings with European allies. It's a possibility not lost on senior administration officials.
House Intelligence Committee Chairman Mike Rogers, R-Michigan, argued the Russian leader is likely eyeing more opportunities in the coming days.
"(Putin) has put all the military units he would need to move into Ukraine on its eastern border and is doing exercises. We see him moving forces in the south in a position where they could take the southern region over to Moldova," Rogers said on NBC's "Meet the Press."
There are other approaches. Obama's former ambassador to Russia, Michael McFaul, urged the administration to intensify its policy of isolating Putin in an op-ed in the New York Times.
"Mr. Putin's Russia has no real allies. We must keep it that way," McFaul wrote.
But the White House is determined to ensure that the President's trip to Europe and Saudi Arabia will be more than just another showdown with Putin.
Hours after Obama landed in The Netherlands for the Nuclear Security Summit, the White House announced a deal to dispose of huge quantifies of nuclear material from Japan.
It's the kind of achievement Obama hoped to spotlight, had this trip not become so complicated.
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