It's said that every senator sees a president in the mirror. It's a cliche, but it's at least 5% true right now.
That's because five of the body's 100 members are now officially presidential candidates. And while lawmakers' career aspirations are always a factor in politics, this early election stampede is causing particular headaches for the White House's current occupant.
Two glaring examples just this week: Surveillance and free trade.
Several provisions of the Patriot Act lapsed on Sunday night after the Senate couldn't agree on how, or if, to reform the law. Most notably was Section 215, which the National Security Agency, as revealed by Edward Snowden, used to justify the bulk collection of Americans phone call information.
President Obama used, and initially defended the NSA's bulk collection program for anti-terror surveillance. It soon became clear that large bipartisan majorities in Congress were intent on significantly altering the practice.
But why the lapse this week? Rand Paul, Kentucky's junior GOP senator and one of the first senators to declare his White House candidacy,has opposed the Patriot Act for his entire political career.
This week he was also able to take advantage of a rare strategic fumble by his Kentucky colleague, Sen. Mitch McConnell, the Majority Leader, to burnish his political cred with libertarian supporters.
"I'm not going to take it anymore!" Paul thundered from the Senate floor Sunday evening as the minutes towards the Patriot Act's expiration ticked away. Above him, a few dozen supporters sat in the gallery wearing red "I Stand with Rand" t-shirts. Away from the floor, Republican colleagues lashed out at Paul for campaign fundraising off the lapse in surveillance authorities he helped create.
"He obviously has a higher priority for his fundraising and for his political ambitions than for the security of the nation," sniped Sen John McCain, R-Ariz, moments after McCain tangled with Paul on the Senate floor.
Sen Ted Cruz, R-Tex., another presidential contender, backed Paul in his efforts. Two other candidates, Sen Marco Rubio, R-Fla., and Sen. Lindsey Graham, R-S.C., were opposed, and the divisions helped put out of reach McConnell's late bid to temporarily extend the Patriot Act untouched.
But the presidential antagonism isn't just coming from Republicans. President Obama is in a battle to save the Trade Promotional Authority (TPA) bill, currently before the House. And the huge Trans Pacific Partnership trade deal, strongly backed by the White House hangs in the balance.
The majority of Republicans, almost all of them free trade supporters, are with Obama on this one. But Democrats are not, and they're threatening to sink the deal entirely when it comes up for a House vote within the next week or two.
Less than 20 Democrats have committed to vote for TPA, and that won't be enough to push it to victory. Even Democratic leaders like Nancy Pelosi, D-Calif. and Steny Hoyer, D-Md., aren't saying how they'll vote.
Opponents have relied on a new public champion as their ranks grow in the House. Sen. Bernie Sanders, a Vermont independent running for the Democratic presidential nomination, has been railing against the deal on the campaign trail in front of larger crowds than many expected the outsider candidate to muster.
"You got Wall Street telling us what a great trade agreement this is. You got drug companies telling us what a great trade agreement this is," Sanders said at a small rally Capitol Hill rally Wednesday.
President Obama has also been telling people what a great agreement it is, including in interviews Wednesday with five local news stations from districts of lawmakers whose votes he desperately needs.
Hillary Clinton, on the other hand, can clearly see the peril Sanders poses with the liberal base of her party on trade. Clinton backed the deal as Secretary of State under President Obama, but so far has made only general statements about the need for such deals to be fair to workers.
Meanwhile, Sanders continues to try and galvanize liberal Democrats in advance of the House vote. A defeat next week would be a major hit for President Obama's trade policy.
Washington's unofficial calendar says that Labor Day before a presidential election year marks the end of substance and the beginning of political show-voting in Congress. It's only June, and while important policy is on the floor, presidential politics is definitely on the agenda.