By MICHAEL FALCONE ( @michaelpfalcone )

NOTABLES

• 'A COST ON RUSSIA': President Obama this morning underscored that Europe and the U.S. are united in support of Ukraine, as he kicked off the European swing of his five day foreign trip, according to ABC's MARY BRUCE. "Europe and America are united in our support of the Ukrainian government and the Ukrainian people. We're united in imposing a cost on Russia for its actions so far," Obama said in a statement after a bilateral meeting with Prime Minister Rutte, shortly after arriving in the Netherlands. Rutte condemned "in the strongest terms" Russia's attempts to annex Crimea, calling it a "flagrant break of international law."

• HAPPENING TODAY: At 1:15 p.m. ET, President Obama meets with the other leaders of the G-7 on the sidelines of the Nuclear Security Summit to discuss the crisis in Ukraine and their response to Russia. In an interview with a Dutch newspaper, Obama reiterated that "There have to be consequences. And if Russia continues to escalate the situation, we need to be prepared to impose a greater cost."

THE ROUNDTABLE:

ABC's RICK KLEIN: The new Senate analysis from our colleagues at FiveThirtyEight.com is the latest warning signal for Democrats in 2014. Its main conclusion, that the GOP holds a 60 percent chance of taking back the Senate, is coming under harsh criticism from Democrats, naturally. The Democratic Senatorial Campaign Committee quickly penned a memo arguing against making such conclusions this early. Naturally, the DSCC included this line: "It has become crystal clear that our opponent in 2014 is not the Republican Party but two billionaire brothers." Democrats are doing all they can to try to bring money of their own into the process, amid frustrations that the Obama operation isn't in high gear for this year. But does anyone think American voters will turn out in the kind of numbers Democrats need to send a message to the Koch brothers? Democrats need a different climate, not simple outside spending to match the Kochs, to overcome the forces at work this year.

ABC's ARLETTE SAENZ: Sen. Marco Rubio, R-Fla., will speak at the Uber offices in Washington, DC Monday afternoon, his second stop at a technology company in as many weeks. Rubio, who has used Uber himself, will discuss the need to overhaul regulations that block new and innovative companies, like Uber, from operating, an aide to Rubio said. Earlier this month at a speech at Google, Rubio pointed out that lawmakers in Miami shot down legislation that would have allowed the popular car service to operate in the county. Today's speech gives Rubio the opportunity to address an issue directly affecting his constituents in Florida while also outlining his economic ideas to the tech industry, an alliance that could be beneficial to him should he run for president in 2016.

ON OBAMA'S AGENDA: President Obama spends the early part of the week in Europe with major stakeholders in the standoff with Russia before visiting the Pope and continuing on to Saudi Arabia. He is accompanied by Secretary of State John Kerry, National Security Adviser Susan Rice and a host of aides. Here's an overview from ABC's CHRIS GOOD:

-TODAY in The Hague, Obama particpated in the Nuclear Security Summit (Obama hosted the first on in Washington in 2009), then attend G7 leaders' meetings on Ukraine later in the day.

-TOMORROW, he meets with leaders from the Netherlands, Abu Dhabi, UAE, South Korea, and Japan and he'll travel to Belgium participate in an EU-U.S. summit and meet with NATO Secretary General Anders Fogh Rasmussen and participate in a trilateral EU/NATO/U.S. meeting.

-THURSDAY, the president will meet with the Pope at the Vatican.

-FRIDAY, Obama will travel to Saudi Arabia for a meeting with King Abdullah. A typically strong U.S. ally, Saudi Arabia has voiced displeasure with inaction on Syria and the west's warming relations with Iran, winning and then rejecting a seat on the UN Security Council out of protest last year. The Obama administration has voiced concerns over Saudi donors' funding of extremist militias in Syria (although Qatar and Kuwait are viewed as the main conduits of Gulf funding for Syrian militias), but earlier this month Saudi Arabia designated ISIS and the Al Nusra Front as terrorist groups.

BUZZ

UKRAINIAN FOREIGN MINISTER: CHANCES OF WAR WITH RUSSIA 'BECOMING HIGHER'. Sunday on "This Week," the acting Ukrainian foreign minister, speaking exclusively with ABC's MARTHA RADDATZ, expressed deep concern about the buildup of Russian troops on the eastern border of Ukraine, saying that the chances of war were "becoming higher." "We are very much concerned about this development, the deployment of Russian troops on our eastern borders," Ukraine's Andrii Deshchytsia said on "This Week," according to ABC's BENJAMIN BELL. "We are ready to respond and, as you know, the Ukraine government is trying to use all the peaceful diplomatic means and diplomatic means to stop Russians but the people are also ready to defend their homeland." Deshchytsia said the issue had become "even more explosive" than a week ago when he was interviewed on "This Week, when he said the chance of war with Russia was "quite high." "I would say if you wanted to measure somehow, it's becoming higher," Deshchytsia said of the chance of war. "Because the problem is that Russians, and particularly the - Putin's administration - Putin himself is not talking to the rest of the world, he doesn't want to listen to the world, he doesn't want to respond on the arguments … to deescalate [the] situation and stop invasion. We don't know what Putin has in his mind and what will be his decision." http://abcn.ws/1gN7RFC

FIVE QUESTIONS WITH FOREIGN POLICY INITIATIVE CO-FOUNDER DAN SENOR. This week, we asked Foreign Policy Initiative Co-Founder Dan Senor to answer five questions. Dan joined the discussion on our powerhouse roundtable Sunday on "This Week." Here's an excerpt from ABC's BEN BELL: 1) How would you grade President Obama in terms of his overall foreign policy? SENOR: "Recall the foreign policy goals that then-candidate Obama proclaimed he would advance as president. He said he would restore America's image abroad, especially in the Muslim world; forge a lasting peace between Israel and the Palestinians; wind down the war in Iraq in order to re-focus on Afghanistan; recalibrate America's relationship with Iran though personal diplomacy; usher in a new era of cooperation with China; and, fundamentally "reset" relations with Russia. Graded against the expectations that he set, perhaps his failures were inevitable. Success on any one of those fronts would have been an impressive achievement. That he hasn't really re-calibrated his approach in spite of persistent failures should worry us about the next few years." http://abcn.ws/1dbvjBv

OBAMACARE TURNS 4: THE (VERY) LONG, STRANGE TRIP TO NOW. This week marks four years since President Obama consummated America's decades-long dalliance with health care reform. The White House's East Room was the venue for the ceremony that day, during which the president, a metallic blue tie around his neck and a light dusting of gray in his hair, applied his powerful signature in 22 clipped dashes - two pens per letter, one for each of his honored guests - to the Affordable Care Act, which we know as Obamacare, the law Republicans say, on this anniversary, will fuel another midterm election sweep. That is, with some flourishes, the narrative of Spring 2014. The story of Obamacare, though, is much stranger. The legislation itself is massive, ground-breaking, and meaningful in a way that goes far beyond the provisional requirements. Obamacare in its four years and all those to come, barring #FullRepeal, is and will be pretty much anything the country wants. The meaning of the troubled rollout of the exchanges remains as open to interpretation as the "individual mandate" was in the hands of the Supreme Court, which on a hot summer morning in 2012, with the president slouching toward reelection, delivered a decision that temporarily baffled supporters, opponents, and many of the experts and professional neutrals waiting on those sprinting interns. Here's is ABC's GREG KRIEG's look back at Obamacare's journey: http://abcn.ws/1kUyCxe

WHAT WE'RE WATCHING

MATT DAMON: 'REAL OPPORTUNITY' TO SAVE PEOPLE THROUGH CLEAN WATER. Matt Damon spoke with ABC's CECILIA VEGA during an interview on "This Week," about his philanthropic efforts to provide worldwide access to clean drinking water, and information about the importance of toilets. An estimated 2.5 billion people lack access to improved sanitation, and 780 million lack access to clean water. It was staggering figures like these that prompted Damon to co-found the non-profit water.org in 2009, notes ABC's HALEY MUSE . "It's just so huge," Damon said. "There's a real opportunity to save a lot of people." Since its inception, water.org has provided safe drinking water and sanitation across three continents by building wells and toilets through donations and microloan programs. "It's really hard for us to relate to it in the West," Damon said. "A clean glass of water is as far as the faucet and we all have toilets." http://abcn.ws/1irq8N3

WHO'S TWEETING?

@bykowicz: Rove & other DC figures loom over NC Senate race. @mccormickjohn untangles the Republican primary. V/ @BloombergNews http://bloom.bg/1oSHmp7

@mviser: "Let me be clear: I am worried," Peter Burling, a DNC member from NH, says of GOP outside spending advantage. http://www.bostonglobe.com/news/politics/2014/03/23/senate-spending-battle-nonprofit-groups-put-republicans-way-ahead/PrHjBTNjOAoYlGNadmPQCP/story.html …

@guycecil: Great story about @dreysamuelson - 28 years as right-hand man for Sen. Johnson http://argusne.ws/1dmruKl

@RichardViguerie: The Left is scared of @SarahPalinUSA. If it were #Hillary vs. Sarah, HRC wouldn't have a chance. #tcot http://bit.ly/1f8FO40 #GOP

@kzernike: Christie's lawyers say it's true; he really did not move the cones: http://nyti.ms/1eDnjI0