Donald Trump did the previously unthinkable this month, raising questions about whether Sen. Ted Cruz (R-Tex.) would be disqualified from the presidency because he was born in Canada. For Trump, it was a legal, albeit politically advantageous, question, and not much more. For Conservative Solutions PAC, the super PAC supporting Sen. Marco Rubio (R-Fla.), it was an opportunity to spice up an attack over Cruz's disruptive tax-reform plan and its "business flat tax." New Hampshire TV viewers are now watching Cruz's face squeezed into a Canadian maple leaf.

super PAC supporting Sen. Marco Rubio (R-Fla.),

That ad complements (without coordination) an attack from Rubio's presidential campaign. Young Rubio volunteers have been appearing at Cruz events, asking reporters not to use their names, and dropping off literature that accuses Cruz of a plan to implement "European-style taxes."

Trump gets the headlines, but it's really Rubio's campaign, and its allies, running the most traditional negative campaign. At a Cruz speech in Belknap County on Tuesday, young Cruz fans showed up with fliers and signs declaring that Cruz used a "political calculator." In case the allegation flew over our heads, reporters were given small pocket calculators, emblazoned with a quote from Rubio about Cruz's — wait for it — "political calculation."

And if even after that, the message is a bit confusing, there's an accompanying TV ad to clear up matters.

A super PAC supporting Sen. Marco Rubio (R-Fla.), released this ad accusing Sen. Ted Cruz (R-Tex.) of switching positions on issues for political convenience.

But Conservative Solutions is not limiting its targets. Radio listeners and TV watchers are also frequently subjected to a spot — 60 seconds and 30 seconds, respectively — that portrays the gubernatorial record of New Jersey Gov. Chris Christie (R) in apocalyptic tones. The radio version also differs in its closing tag: "High taxes, a weak economy and scandals. That's the last thing we need in the White House — again." There's no "again" on TV.

A super PAC supporting Sen. Marco Rubio (R-Fla.), released this ad attacking New Jersey Gov. Chris Christie (R).

That spot was the PAC's second attempt at a Christie-slayer, after a kitchen-sink style ad that went up two weeks ago, and ended with perhaps the least subtle tag of the cycle.

Rubio is only the latest in a long, proud history of candidates going negative to bolster their positions. What's notable about his multi-pronged attacks in New Hampshire is just how many directions they're going in — and how they ignore the state's front-runner, Trump.

Rubio is one of five candidates who insist that merely coming out of the state looking competitive (becoming "a story," as Ohio Gov. John Kasich puts it) would be enough to position them for later primaries. Their shared immediate problem is that the other people in that position have become fairly popular among Republican voters. In most surveys, Rubio, Christie, Cruz, and Kasich enjoy double-digit net favorable ratings. For Christie and Kasich, that has required a great deal of retail campaigning and positive-ad spending.

Rubio, still the de facto second choice of most Republicans, does not lap his rivals in favorability anymore. The solution for him is this campaign of individual disqualification.