Democrats are targeting red states like Alaska and Texas, but they worry about tight races in blue states like Minnesota and Maine. Matt Bennett said, "They are weaker nominees than we had hoped there would be." These close contests force the party to spend extra time and money to win.

Reporting from Minnesota, with stops in Minneapolis, St. Paul, St. Louis Park and West St. Paul.

President Trump's low approval ratings have given Democrats a chance to win Senate races in red states like Alaska, Iowa, Texas and Kansas for the first time in a generation.

But at the same time, Democrats in blue states like Minnesota and Maine and battlegrounds like Michigan remain locked in close races where the party's nominees could jeopardize a Senate majority if they falter in winnable contests.

These too-close-for-comfort races for Democrats are each in states where the party, in varying ways, has created its own political headwinds. All three also feature progressive Democrats who won their nominations over the objections of party leaders who backed more moderate rivals.

"I hope they win -- we want them to win," said Matt Bennett, a co-founder of Third Way, a moderate Democratic think tank. "But they are weaker nominees than we had hoped there would be and it means we have to spend money and time, and there are all kinds of things we have to do that we would not if we had stronger nominees."

In Michigan, Dr. Abdul El-Sayed still faces vocal resistance from some moderate and Jewish voters in his race against former Representative Mike Rogers, a Republican, after one of this year's most hostile Democratic primaries. In Maine, Troy Jackson, who was subbed in as the Democratic nominee in July after the implosion of Graham Platner's campaign, trailed Senator Susan Collins in the most recent New York Times/Siena University poll.

And in Minnesota, Lt. Gov. Peggy Flanagan is being dogged by the state's major fraud scandal in her contest against Michele Tafoya, a Republican former sports broadcaster. Ms. Tafoya is trying to appeal to the political middle by running TV ads that declare herself to be "a pro-choice Republican" and feature a parade of Democrats who say they are voting for her.

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