To no one’s surprise, Rep. Tom Cotton (R-Ark.) will be announcing his run for the U.S. Senate next week, according to multiple news reports. This turns Sen. Mark Pryor (D-Ark.), already in trouble in his bid for reelection, into an endangered species.

Tom Cotton Rep. Tom Cotton (Manuel Balce Ceneta/Associated Press)

Conservatives of all stripes should be excited. American Crossroads issued a statement, reading in part: “One of the weakest Democrats in the Senate this cycle is now facing potentially the strongest Republican challenger of the cycle. Representative Cotton is a conservative leader and rock star candidate. Arkansas is now one of the very top pickup opportunities for Republicans this cycle and we are excited to get engaged in the race on behalf of Rep. Tom Cotton.”

Cotton is not simply a rock-ribbed Republican. He’s a veteran of the Iraq and Afghanistan wars, holds a Harvard law degree and is a farmer. Most important, he’s a critical voice in the current debate over America’s role in the world. (My previous interview with him can be read here.)

There are few people on the national stage as informed and articulate as Cotton when it comes to national security. Most recently, he has spoken out forcefully against the foolish attempt to strip funding from the NSA surveillance program. He, along with others such as Sens. Marco Rubio (R-Fla.) and Kelly Ayotte (R-N.H.), is part of a new generation of pro-defense lawmakers who are capable of engaging anti-military isolationists on the left and right. He will no doubt take on a raft of national security (not to mention domestic) issues including these:

How do we restore appropriate military funding while reforming the Pentagon to get the greatest value for each taxpayer dollar?

How do we restore our credibility in the Middle East?

How do we stop Russia and China from pushing us around?

What is the value of anti-terrorist programs currently in place?

How is our economic livelihood tied to America’s superpower status?

Cotton has a rationale for his candidacy beyond simply replacing a lackluster Democrat who is out of step with his state. Whether you call it restoring U.S. power or arresting U.S. retrenchment, voters will know there is a purpose to his candidacy and a unique contribution he can make to the Senate. That is precisely what every GOP challenger should have.

It is not enough to rail at Obamacare or advocate useless objectives. That is the luxury of a minority party. Senators and senatorial candidates with a bigger vision who want to be in the majority need to sketch out what they would do, not what they will be against.

That is the irony of the right-wing grandstanders in the Senate. They imagine they are doing damage to the president. (Or maybe they are honest enough with themselves to admit this is about fundraising and self-promotion.) The real damage to Obama would be in delivering a Senate majority made of competent and clear-eyed Republicans in whom the public can put their trust to restrain the president and get the best deals possible, be it on taxes or energy or anything else. If the Senate pot-stirrers really wanted to make trouble for the Dems, they’d support candidates like Tom Cotton and make the case to the voters that the final two years of Obama’s term will be an unmitigated disaster if the Senate stays in Democratic hands and the House flips control (both of which are possible).

For now, we can look forward to at least one Senate campaign about something substantive — the survival of the Free World.