Pablo Martinez Monsivais/AP

The Senate on Thursday night returned to one of its odder occasional traditions: a round-the-clock session in which a legislative body full of lawmakers in their 60s and 70s stays up all night to vote on budget amendments. The end result was that shortly before 3:30 a.m. Friday, the Republican majority passed, by a vote of 52-46, a budget resolution that party leaders will try to reconcile with the more conservative measure the House approved last week.

The underlying resolution doesn't have the force of law, but in a chamber known more for endless talking than for actually voting, the aptly-named vote-a-rama can be surprisingly revealing about where senators stand on major issues at the moment. Members of both parties use the opportunity to force their colleagues to take a stand on controversial topics, knowing that their votes could wind up in campaign ads down the road. (My colleague David Graham explained how it worked during the Senate's last budget all-nighter in 2013.) While many of the more than 40 votes this year fell predictably along party lines, a filibuster-proof majority of 61 senators supported paid sick leave, a simple majority backed federal benefits for legally-married gay couples, and the Senate stood unanimously for increased sanctions on Iran.

Here's a look at some of the more notable votes:

Paid Sick Leave

Democrats have made ensuring that workers have paid sick leave a priority in recent months, yet it was assumed this issue would stall under Republicans who oppose subjecting businesses to new regulation. Not necessarily. An amendment offered by Senator Patty Murray of Washington state earned the votes of 14 GOP senators, giving it enough to overcome a filibuster and make it into the final budget resolution. Does this mean the Senate will pass it into law anytime soon? No. Majority Leader Mitch McConnell opposed the amendment and could prevent it from coming up in the form of legislation, and even if it did, senators wouldn't be held to their non-binding budget vote. But the strong support shown on Thursday indicated an unexpected consensus in the Senate, giving the push for mandatory paid sick leave new momentum.

Same-Sex Marriage

The Senate didn't hold a direct vote on whether gay marriage should be allowed, but Democrat Brian Schatz of Hawaii asked his colleagues whether legally-married, same-sex spouses should have "equal access to the Social Security and veterans benefits they have earned and receive equal treatment under the law pursuant to the Constitution of the United States." Fifty-seven senators voted that they should, including all 46 Democrats and 11 Republicans. With the Supreme Court set to rule on same-sex marriage later this year, federal recognition and benefits for gay spouses could become a fait accompli. But the clear majority support in a Republican-controlled Senate—unthinkable during the last GOP majority a decade ago—is yet another indication of how rapidly public opinion has shifted on the issue in recent years.

Social Security

Nowhere was the Senate more divided than on the issue of Social Security. A group of Democrats including Elizabeth Warren, the liberal favorite, and Joe Manchin, a West Virginia moderate, put forward an amendment calling for an expansion of Social Security, so long as it didn't add to the deficit. Every Republican and two Democrats opposed it, but the near-unanimous backing from Democrats on an issue popular with the progressive movement was significant. After years in which the White House and many congressional Democrats were entertaining the idea of trimming entitlement programs as part of a fiscal grand bargain, the party is now rallying around a proposal that would expand benefits.

Iran Sanctions

One of the few unanimous votes of the night centered on Iran sanctions, which is a delicate topic given the Obama administration's opposition to separate legislation that, it argues, would undermine its negotiations for a nuclear agreement. The budget amendment from Republican Mark Kirk of Illinois didn't address the wisdom of a deal with Iran, but it called for reimposing sanctions if the Iranians violated any agreement that is reached. An amendment from freshman Tom Cotton voicing support for Israel also drew no opposition.

Defense Spending

The size of the Pentagon's budget divided Republicans in the House, and it caused a similar fissure in the Senate. But the votes on Thursday were more notable for the way they reflected jockeying for position in the presidential campaign. Senator Rand Paul of Kentucky, who plans to launch his White House bid next month, proposed a change that would add $190 billion in defense spending while offsetting the boost with cuts to domestic programs. All but four Republicans rejected the proposal. Another likely 2016 contender, Marco Rubio of Florida, offered a competing amendment to increase the Pentagon spending without paying for it elsewhere. That change failed, too, but it earned far more GOP support. The Senate Republican who has already announced his presidential candidacy, Ted Cruz, "appeared torn over how to vote on Rubio’s measure," Politico reported, "standing at the well of the chamber and staring at the text of the legislation before voting yes." The 2016 hopefuls also split on the final budget vote: Rubio and Senator Lindsey Graham supported the Republican plan, while Paul and Cruz were the only two GOP lawmakers to oppose it.

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