The two sides battling over Amendment 68 now have raised $33 million and spent almost $29 million of that.
Two groups bought almost $850,000 in ads on Spanish-language channels in Denver and Colorado Springs.
The anniversary of last year’s devastating floods has become a talking point in Colorado's U.S. Senate campaign.
They want the Obama Administration to take action now and not wait until after the election.
The law Rep. Cory Gardner touts in a campaign ad for his Senate bid was repealed five years later after being deemed useless.
Nearly $29 million is going into a battle over casino gambling.
Africans make up Colorado's second-largest immigrant group, but until recently, they haven't played much of a role in the state's political life. That's changing now.
Ads purchased by outside groups make up more than $38 million – almost 77 percent – of the total spending so far in Colorado.
Democratic candidates and groups are outspending Republicans so far.