U.S. finds itself on both sides of proxy war between Iran and Saudi Arabia… That proxy war complicates any nuclear deal with Iran… Scott Walker: I’ll tear up any nuclear agreement with Iran on my first day as president… On Joe Biden and 2016: Why he isn’t part of the conversation… And John Boehner’s good week.

FIRST THOUGHTS.

*** U.S. finds itself on both sides of proxy war between Iran and Saudi Arabia: Talk about the United States being in a difficult place. One hour, the U.S. is conducting airstrikes to combat Sunni extremists – ISIS – in Iraq. “U.S. warplanes are now conducting airstrikes in support of Iraqi efforts to take the city of Tikrit from the terror group ISIS, the U.S. military said Wednesday,” per NBC News. The next hour, it’s helping aid Saudi Arabia’s bombing campaign against Shiite extremists – the Houthi rebels – in Yemen. “Secretary of State John Kerry commended the work of the coalition and underlined U.S. support for the effort — including intelligence sharing, targeting assistance, and advisory and logistical assistance — in talks with his counterparts in the region on Thursday,” according to a separate NBC report. The backdrop, of course, is the clear proxy war in the Middle East between Shiite Iran and Sunni Saudi Arabia. But as the New York Times writes, one of the reasons why the United States has taken a more active role in the bombing campaign in Iraq is because it’s worried that Iran now has too much influence in the country. “If the Americans did not engage, they feared becoming marginalized by Tehran in a country where they had spilled much blood in the last decade, the officials said, speaking on condition of anonymity.”

*** That proxy war complicates any nuclear deal with Iran: This proxy war between Iran and Saudi Arabia also makes a complicated nuclear deal with Iran even more complicated. And as with most deals, the last-minute negotiations are always the hardest. “Over the past few weeks, Iran has increasingly resisted any kind of formal ‘framework’ agreement at this stage in the negotiations, preferring a more general statement of ‘understanding’ followed by a final accord in June, according to Western diplomats involved in the talks,” the New York Times says. “Should that position hold — one of the many unknowns of the coming days — the United States and its five negotiating partners may find themselves in the uncomfortable position of describing the accord as they understand it while the Iranians go home to offer their own version. That poses a weighty political challenge to the Obama administration.” As the LA Times notes, the Iran talks restarted today, and March 31 is the firm deadline to reach a deal.

*** Scott Walker: I’ll tear up any nuclear agreement with Iran on my first day as president: Speaking of the nuclear the United States and other countries (Britain, France, Germany, China, and Russia) are trying to strike with Iran, Scott Walker said he’d reject the agreement on his first day in the White House. The Hill: “In an interview on Hugh Hewitt’s radio show, the host asked Walker whether he would ‘disown’ any agreement between the U.S. and Iran that allows for uranium enrichment if he wins the presidency in 2016. ‘Absolutely,’ Walker said. ‘On day one.’” It is worth pointing out how all the GOP presidential promises – repeal Obamacare, enact the GOP budgets, confrontation with Iran – could make the first 100 days in a Scott Walker/Jeb Bush/Marco Rubio/etc administration a problem. Talk about having almost NO honeymoon after wading into those thorny (and likely politically taxing) issues. Then again, that’s something Walker has plenty of experience with – see his 2011 union fight. But as we all know, what happens in Washington (especially when you control the White House) gets more attention than you ever got in your state capital.

*** On Joe Biden and 2016: Why he isn’t part of the conversation: Be sure not to miss the piece by MSNBC’s Alex Seitz-Wald on Vice President Joe Biden and the fact that he’s unlikely to run in 2016. “Interviews with more than a dozen people close to the vice president paint a picture of a politician torn between a decades-long aspiration for the presidency, a deep commitment his family and a recognition of a political reality tilted against him. For reasons both bigger and smaller than Hillary Clinton, Biden will not achieve the dream to which he’s now come so close. But he refuses to rule himself out completely and will keep a presidential pilot light burning as long as possible. If nothing else, the fiercely loyal Biden will use these next two years to defend the legacy of the Obama administration and his role in it.” The key reason why Biden isn’t in the 2016 conversation: “[W]hat Biden has not yet done is take the substantive steps necessary behind the scenes to prepare for presidential run.”

*** Boehner’s good week: As we’ve seen over the past four years, John Boehner hasn’t always had an easy time as House speaker – just see that failed DHS-funding vote from a few weeks ago. But he’s closing in on arguably his most productive week as speaker with 1) the Medicare doc-fix compromise with House Minority Leader Nancy Pelosi, and 2) the budget House Republicans passed last night. (Yes, the House passing budgets has normally been an easy affair, but this time having to navigate between his party’s fiscal hawks and defense hawks wasn’t easy). Now both of these matters aren’t final until the Senate weighs in, but this has been a good week for Boehner.

OBAMA AGENDA:

From the AP: “Saudi Arabia bombed key military installations in Yemen on Thursday after announcing a broad regional coalition to oust Shiite rebels that forced the country’s embattled president to flee. Some of the strikes hit positions in the country’s capital, Sanaa, and flattened a number of homes near the international airport.”

Writes the Washington Post: “[A]s the end of Obama’s presidency draws closer, his pragmatism is increasingly colliding with his strongly held belief that U.S. military power will never be able to fix the problems in Iraq and Afghanistan. Without a clear end date, senior White House officials warn that the U.S. role in the wars will go on forever.”

The U.S.-Iran talks have restarted as U.S. officials say they still view March 31 as a firm deadline for an initial agreement.

CONGRESS: House passes GOP budget; Senate up next

The Senate is up next after the House passed its conservative budget last night.

POLITICO previews tonight’s vote-a-rama in the Senate.

House Speaker John Boehner makes his case for the doc fix bill in National Review: “Make no mistake — this bill is not perfect. But it is an opportunity to solve a problem permanently and improve Medicare in the process. We should seize that opportunity and do some good for the American people.”

The Wall Street Journal lays out where we are with the doc fix now as resistance among Senate Democrats seems to be waning.

OFF TO THE RACES: After race to right, can GOP tack to the middle?

McClatchy’s Lightman: “The 2016 Republican presidential candidates figure that to win the party’s nomination, they have to get cozy with hardcore conservatives. But to win the general election, they have to move away from that same constituency. It’s a quadrennial predicament that’s bedeviled Republican White House hopefuls since the rise of the Moral Majority and the Christian right 35 years ago. Those interest groups are powerful and persistent, committed to a mission that would recast the party as God-fearing champions of limited government and individual freedom.”

Per a release, “On the heels of the first presidential candidate announcement, Mike Rogers, former Chairman of the House Intelligence Committee, is announcing the New Hampshire leadership of Americans for Peace, Prosperity and Security (APPS) at an event in Manchester today.”

BUSH: The New York Times (with an Oskaloosa dateline) goes behind the scenes of the conservative movement to unite behind someone whose last name isn’t Bush.

And msnbc.com’s Steve Kornacki writes about the significant resistance to Bush among his own party’s rank-and-file.

The Boston Globe: “Jeb Bush takes a firm line on lraq”

BIDEN: Msnbc.com’s Alex Seitz-Wald reports on the latest from Bidenworld: “Interviews with more than a dozen people close to the vice president paint a picture of a politician torn between a decades-long aspiration for the presidency, a deep commitment his family and a recognition of a political reality tilted against him.” MORE: “For reasons both bigger and smaller than Hillary Clinton, Biden will not achieve the dream to which he’s now come so close. But he refuses to rule himself out completely and will keep a presidential pilot light burning as long as possible. If nothing else, the fiercely loyal Biden will use these next two years to defend the legacy of the Obama administration and his role in it. “

CLINTON: POLITICO reports on her new tech team and what it shows about her 2016 strategy.

CRUZ: Msnbc.com’s Aliyah Frumin and Ali Vitali caught up with him at a young professionals event in Manhattan.

JINDAL: It turns out that the Louisiana governor is a gym rat, per msnbc.com

PAUL: From Time: “In an olive branch to defense hawks hell-bent on curtailing his White House ambitions, the libertarian Senator introduced a budget amendment late Wednesday calling for a nearly $190 billion infusion to the defense budget over the next two years—a roughly 16% increase.”

SANDERS: Bloomberg notes: Bernie Sanders needs the thing he hates the most - money in politics - to mount a real challenge to Hillary Clinton.

WALKER: He says he would reject a deal with Iran on “day one” of his presidency.

And around the country…

NEW JERSEY: Prosecutors are trying to get one of Sen. Bob Menendez’s top friends and donors to cooperate as a witness in the senator’s corruption case, writes the New York Times.

NEW YORK: The New York Times profiles Chirlane McCray, writing that she is less involved in the day-to-day running of New York City than expected.

Additional reporting by Carrie Dann.