Senate Majority Leader Mitch McConnell (R-Ky.), accompanied by Sen. Mike Enzi, R-Wyo., speaks to reporters on Capitol Hill in Washington, Tuesday, March 24, 2015, following a policy luncheon. (AP Photo/Pablo Martinez Monsivais)

Senators are bracing for what is shaping up to be a very long day -- and night -- of federal budget votes in a politically-charged marathon session that's been dubbed "Vote-a-rama."

The lawmakers started voting on dozens of amendments to the Republican budget proposal around noon, and they probably won't wrap up until early Friday morning. The amendments are aimed at drawing attention to senators' pet political causes, forcing others to weigh in on big debates and most notably, causing headaches for the members of the opposing political party.

Those political headaches could resonate in both the presidential campaign and the battle for the Senate. Four Republican senators are either eyeing White House bids or have already launched them. And Democrats are trying to retake the Senate majority they lost in the 2014 GOP wave election mainly by targeting Republican incumbents up for reelection in blue and purple states.

The budget is a framework for the appropriations process, not a law. So the amendments are not part of a bill that will ever go to the president's desk. But they do offer a snapshot of what both parties believe to be good politics moving toward a pivotal election.

Opening the Senate's business Thursday morning, Majority Leader Mitch McConnell (R-Ky.) previewed some of the battle lines and hinted that the session could stretch on for hours.

"Tonight the American people will have their voices heard here in the Senate under new management," said McConnell. He later added: "We'll finish the process just as early as members would like to finish the process."

There are already 62 pending amendments before the Senate, including several sponsored by Democratic senators calling for free community college tuition financed by raising taxes on the wealthy, paid sick time, a restoration of federal student loan reductions and protections for American jobs. Democrats say these amendments could cause problems for some of their Republican colleagues.

Speaking on the Senate floor, McConnell suggested Democrats will face politically sensitive votes too, saying senators will have to choose between "a policy that could cost up to a million jobs" or standing "tall for American jobs instead"; "more tired tax hikes" or protecting jobs threatened by such hikes; and raising energy costs or seeing Americans "reap benefits of our energy revolution."

As Minority Leader Harry M. Reid (D-Nev.) noted, Republicans "have a totally different vision" from Democrats on where to take the country in the coming years.

In other words: Depending on how key members of both parties vote, the day's activities could resurface again and again in campaign mailers, stump speeches and attack ads in 2016.

Meanwhile, the heated debate over how to deal with Iran that is unfolding against the backdrop of the Obama administration's nuclear talks with the country will also come under the spotlight. Sen. Mark Kirk (R-Ill.) is introducing an amendment raising the prospect of new sanctions against Iran.

The Republican-controlled House passed a budget proposal on Wednesday that would spend nearly $3.8 trillion in 2016 and projects revenue of just under $3.5 trillion for the next fiscal year. Republicans say the plan would balance the federal budget and create a surplus by 2024.

The proposal would also provide nearly $100 billion in an off-budget account to fight terrorism abroad. Defense hawks demanded the money to supplement Pentagon spending that was set in line with limits imposed by the 2011 across-the-board cuts known as sequestration.

The budget's passage marked a much-needed win for Speaker John A. Boehner (R-Ohio), who has struggled to corral an unruly group of rank-and-file members.

Once the Senate finishes its marathon amendment process it will vote on the budget proposal, which is expected to pass along party lines. Then the House and Senate will come together in a conference to hash out the differences between their respective budget frameworks.