Republican presidential candidate Marco Rubio took aim at Donald Trump Feb. 28, criticizing his rival's "small hands" and "spray tan." (Marco Rubio)

If it insults, it leads.

This has long been the story of the 2016 Republican presidential campaign, when it comes to cable news. Barb-master Donald Trump has dominated the television airwaves since entering the race last summer, earning as many mentions on the air as the rest of his rivals combined, according to data from the Internet Archive. That amounts to a massive in-kind donation from CNN, MSNBC, Fox and other networks to the Trump campaign, in a year when free media has been far more valuable than paid advertising.

In the last week, one of Trump's rivals finally began to use this phenomenon to his own advantage. Marco Rubio began insulting Trump at every turn, first in a televised debate on Thursday night, and then in campaign rallies thereafter. Rubio has swiped at Trump's policy knowledge, his vanity, even the size of his, um, hands. His television time has spiked accordingly:


Note, though, that Trump's mentions have spiked as well. That's what happens when you insult someone on TV - you draw attention to him as well as to yourself. So Rubio's new strategy is, in pure attention-driving terms, helping both Rubio and Trump.

It's hurting Ted Cruz. His mentions have fallen in recent days, in the run-up to Super Tuesday; on Saturday, the day after Chris Christie endorsed Trump, Christie alone was mentioned more than Cruz.

The attention shift might not worry Cruz that much. There's no guarantee that airtime will translate into success at the ballot box. Other metrics of voter interest suggest Rubio's strategy has been less attention-getting. The Florida senator briefly pulled ahead of Cruz in Google search traffic this weekend, for example, but they're back to about even now:


Google Trends