The Senate was in the midst of overhauling a key section of the USA Patriot Act when Republican Sen. Rand Paul launched his next congressional expedition.

Alongside the families of Sept. 11 victims, Paul announced Tuesday morning he was sponsoring the Transparency for the Families of 9/11 Act, legislation that would force authorities to disclose 28 pages of a 9/11 report that have remained secret for more than a decade.

"We cannot let page after page of blanked out documents be obscured behind a veil, leaving these families to wonder if there is additional information surrounding these horrible acts," Paul said, adding that he plans to bring the bill up as an amendment to the National Defense Authorization Act in upcoming weeks. Fresh off a fight over government spying, Paul is ready to go another round in the name of government transparency.

For Paul, the latest crusade—albeit smaller than taking on the NSA, and less likely to yield substantial press attention—highlights the senator's ability to rally around niche topics that have broad resonance in his base. Government secrecy has long been a rallying cry for libertarian-leaning voters. The freshman from Kentucky, though, is hardly a legislative wheeler and dealer. He is obstinate, but that's what his supporters want. And with his focus squarely on the 2016 presidential election, doing what he can to keep the base engaged is what counts.

Much to the chagrin of many of his hawkish colleagues, Paul has spent the last several weeks pushing to end a national security program that allows the collection of Americans' phone metadata. Two weeks ago, he railed against government surveillance programs on the Senate floor for more than 10 hours. Then, by blocking a short-term extension of the program, Paul helped catapult the Senate into a rare Sunday session. And even in the final days of the debate, Paul stood in the way of the Senate inevitably passing a reform bill that he believed did not go far enough.

"I think he rang this bill till it cracked and it's not the Liberty Bell," said Kansas Republican Sen. Pat Roberts, who has been a fierce defender of the Patriot Act.

But Paul is not looking to win a popularity contest within the Senate. He needs to win the race of public opinion and raise his profile among grassroots donors. Unlike competitors such as Jeb Bush or even fellow Sen. Marco Rubio, Paul has struggled to tap into the donor class that many campaigns rely on. So, from the Senate floor during his battle against the NSA, Paul's campaign raked in money. Supporters took selfies and tweeted that they "stand with Rand." The Paul-endorsed America's Liberty super PAC even played up Paul's big fight by producing a fire-breathing ad depicting Paul's 2016 presidential competitors Sens. Ted Cruz and Lindsey Graham as Obama henchmen and Paul as a toned-up crusader for civil liberties. That outlandish strategy works for Paul.

Jesse Benton, a spokesperson for the PAC, said that the video had brought in new donors. He declined to say how many or how much was raised.

"You do something like that, you always risk turning people off," he said. "But we're hoping and seeing potential Rand Paul donors are savvy. They understand marketing, they understand having to get attention. They're appreciative of the technique."

In upcoming months, Paul, as well as other presidential contenders, will have a lot of chances to take their campaign strategies straight to the Senate floor.

The Senate now has moved on to consider NDAA, giving Paul a chance to beat the drum on his Sept. 11 survivors bill, or perhaps even talk more about foreign aid. A debate over the reauthorization of the Export-Import bank at the end of the month will give Paul another chance to align himself with libertarians who view the bank as a kind of crony capitalism. There is expected to be a debate on a bipartisan education bill, legislation on cybersecurity, and perhaps even more movement on one of Paul's most talked-about issue: criminal justice reform. Paul's Senate office and his campaign declined to give more specifics about where the presidential candidate is going to spend his political capital.

Still, just because the NSA fight is coming to a close, does not mean Paul's time in the Senate spotlight is over.

"The bright line of the past seems to become a little dimmer in the separation of campaigns and the use of the floor. [It's] a very dangerous thing, so I hope people will refrain from letting that line be blurred at all," said Sen. Richard Burr, the chairman of the Senate's Intelligence Committee.

Paul's NSA gambit may mark the start of presidential contender's fundraisers from the floor. Paul's attempts to bring small donors into his campaign over the past few days by tying presidential politics to floor fights aren't likely to let up. After holding up the USA Freedom Act, Paul claimed in a tweet that he and donors had stopped the NSA"s bulk collection of metadata.

Fellow lawmakers are bracing themselves for more of what they just saw from Paul.

"We should get used to it. That is what the next year and a half is going to be like," Democratic Sen. Chris Murphy said. "The Republican leader is sort of putting the floor in the hands of the presidential contenders in his caucus. When you leave everything to the last minute, you leave tremendous power to senators who can raise a lot of money by forcing the issue."


Shane Goldmacher and Alex Rogers contributed to this article

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