Sen. Cory Gardner is facing a challenge from former Colorado Gov. John Hickenlooper in the November election for one of Colorado's Senate seats.

Colorado’s Republican U.S. Sen. Cory Gardner has effectively been a top target for Giffords, a national group pushing for more gun-control legislation and candidates willing to champion those measures, since its inception four years ago, said Joanna Belanger, the organization’s political director.

In fact, Belanger says, Giffords has been engaged in a “years-long effort to make sure that Gardner doesn’t serve another term.”

And the deep-pocketed group named after former U.S. Rep. Gabby Giffords, an Arizona Democrat who was critically wounded in a 2011 shooting, has invested heavily in Colorado to accomplish that very goal. 

Giffords PAC has dropped more than $1.3 million so far this election cycle in opposition to Gardner, running TV and digital ads and hosting rallies in Colorado on behalf of the Democratic candidate in the race, former Gov. John Hickenlooper. That’s in addition to the $1 million spent in the state by another gun-control advocacy group, Everytown for Gun Safety, which is funded by former New York Mayor Mike Bloomberg.

It’s a dramatic turn from 2014, the year Gardner was first elected to his seat with the help of millions from the National Rifle Association. Gun-control groups really weren’t a financial force back then, making the race a lopsided example of the firearm industry’s power. 

Now the tables