Sen. Lamar AlexanderLamar AlexanderGroups warn of rural health 'crisis' under ObamaCare repeal Trump’s Army pick faces tough confirmation fight Trump faces risky ObamaCare choice MORE (R-Tenn.), boosted by a significant second-quarter fundraising sum, is going on air with an ad that features Sen. Rand PaulRand PaulWe can put America first by preventing public health disasters Conservative activists want action from Trump McConnell: 'Big challenge' to pass ObamaCare repeal in Senate MORE (R-Ky.) touting his work defending fishing access.

Alexander brought in $2 million in the second quarter, a campaign aide confirmed, and is going on air with a $180,000 buy.

The aide said Alexander had already planned to go up with reelection ads early in the 2014 cycle and decided to focus the ad on the Freedom to Fish Act because it's an issue Tennesseans care about.

But it's also an issue that allows Alexander to highlight his work curbing government regulations, something that appeals to Tea Party voters.

Conservatives have indicated they'd like to challenge Alexander in a primary next year, with the Senate Conservatives Fund telling supporters last week that his vote for the immigration reform measure that passed the Senate makes him open to a primary challenger that they'd be willing to back.

"We don't want a government that's strong enough to make our lives risk-free. We can do that for ourselves," Alexander says in the video.

Paul's inclusion in the video is designeded to boost Alexander's credibility among the grassroots Tea Party activists. 

"Nobody wants to say no to Lamar Alexander," Paul says in the ad.

The Freedom to Fish Act also features prominently in a Web video released by the campaign of Senate Minority Leader Mitch McConnellMitch McConnellFive fights for Trump’s first year Warren builds her brand with 2020 down the road AACR’s march on Washington MORE (R-Ky.), who is also considered to be vulnerable to a primary challenge.

Watch the ad: