Colorado Sen. Cory Gardner is the most endangered Republican incumbent this fall. But the GOP has been slightly more optimistic about the race over the past few weeks after Democratic frontrunner, former Gov. John Hickenlooper has had several stumbles and gaffes.

Hickenlooper is still the heavy favorite to win the nomination Tuesday, where he will face off against former state House Speaker Andrew Romanoff. Democratic groups backing Hickenlooper have poured in millions of dollars in ads over the past month as it seemed as though the more progressive Romanoff might pose a threat. But public polling shows Hickenlooper still in a good position to win the nomination. Even his missteps may not threaten his general election standing as much as Republicans hope in a state that has rapidly moved toward Democrats over the past few election cycles.

A SurveyUSA poll for 9News/ColoradoPolitics.com taken June 19-24 found Hickenlooper with a 30 point lead over Romanoff, 58%-28%. A Myers Research poll taken for the Romanoff campaign on June 16 and 17 had shown Hickenlooper up by just a 12 point margin.

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