Polls are showing Donald Trump gaining on Hillary Clinton in Colorado, even as team Clinton thought the Centennial State was wrapped up. Democrats now worry that mail-in voting and lack of enthusiasm among progressives could be hurting Clinton in Colorado.

Even Hillary’s internal polling is showing the race tightening and outside surveys tend to agree; Trump is on the rise in Colorado despite spending little time or money there.

Aside from funding two dozen offices and paying up to 200 staffers, team Clinton stopped putting campaign money into Colorado as far back as the beginning of August, imagining that Colorado was firmly in the Clinton camp. But the new polling is shaking Democrats’ self-assuredness, the Washington Post says.

Polls early in August showed Clinton leading Trump by 14 points, but Hillary’s internals now show that lead dropping to only seven points and other polls show Trump has narrowed the gap to even five points in a four-way race with the Libertarian and Green parties. Still another survey shows Trump only two points down in a head-to-head race with Clinton, the paper noted.

Aside from the tightening polls, the Post cites several other worries that are suddenly dogging Clinton’s Colorado backers. First, they worry that enthusiasm for Clinton is at a low ebb. This is a chronic problem for Clinton all across the country.

As Donald Trump continues to speak to packed houses everywhere he goes, Clinton has often had problems filling venues and Democrats have been fretting about the enthusiasm gap all year.

Another worry seems to be the state’s unique mail-in ballot scheme. Some Democrats worry that many young voters may skip voting altogether over the rigmarole of filling out a paper ballot, putting it in an envelope, and finding a stamp to mail it in–especially since so many young people are geared to the electronic age.

Still, Trump has as few as ten offices state wide and has only this month begun to air TV commercials after Clinton dominated the airwaves all summer. Trump likely has a long way to go in a state filled with voters to whom pundits say he doesn’t appeal.

Follow Warner Todd Huston on Twitter @warnerthuston or email the author at igcolonel@hotmail.com.