Dean Phillips, left, and Angie Craig flipped suburban House seats, but Craig faced a more closely divided district. (Mike Nelson/The Minnesota Star Tribune)

In retrospect, the Third Congressional District wasn't even that close. This shouldn't minimize the achievement of U.S. Rep.-elect Dean Phillips, the Democratic businessman who beat an experienced, well-financed incumbent in Rep. Erik Paulsen.

But the voter profile of the suburban Third District made this ripe for a Democratic flip. Of the 42 House seats that Democrats took from Republicans around the country, two-thirds have a Whole Foods, according to Dave Wasserman of the Cook Political Report. The Third District has two of them, and Phillips beat Paulsen by almost 12 points.

These well-educated, well-to-do voters — the kind who shop at organic groceries — largely supported Hillary Clinton in 2016, and many stuck with Paulsen that time. This year, they registered disapproval with President Donald Trump by voting against Republicans up and down the ballot, as outgoing Minnesota House Speaker Kurt Daudt told me ruefully last week. Suburban losses also cost Daudt his speaker's gavel.

But the Second District is a different case. Rep. Jason Lewis, with just a single term in the House and far less money to defend himself than Paulsen, came much closer to hanging on against Angie Craig, who won by more than 5 points. The Second District has no Whole Foods, and it narrowly supported Trump in 2016.

Exit polling in the Second District by St. Olaf political scientist Christopher Chapp and his students illustrates Republicans' 2018 problems, which are probably a bellwether for the party's dilemma nationwide. They didn't just lose Clinton districts; they lost ground in many closer Trump districts.

Chapp and his students also polled in 2016, when Lewis and Craig faced off for the first time. He sent me three main takeaways.

In the closing weeks of the campaign, Trump worked to make the race a referendum on him. It worked, but perhaps not how he envisioned: A big majority of Democrats wanted to send a message about Trump, according to the exit poll. Only a quarter of the Democrats polled said views of Trump didn't influence their vote, which probably prevented Lewis from picking off some moderate Democrats who might otherwise have been inclined to support an incumbent in a good economy.

Next, Democrats won independents. After splitting the independent vote in 2016, Craig carried independent voters by a whopping 20 points. This illustrates a problem for Republicans around the country. Chapp cited an NBC News exit poll showing Democrats winning independent voters for the first time since 2008. Given their smaller base, Republicans have to win some independents.

Finally, while Democrats tried to make the election about health care, Republicans wanted to make it about immigration. The poll showed Craig winning on both issues, as she picked up some Republican immigration doves and Obamacare supporters, while consolidating Democratic support.

This is a true tossup district, but Republicans have work to do if they are to win it back.

J. Patrick Coolican 651-925-5042 Twitter: @jpcoolican patrick.coolican@startribune.com

Both Dean Phillips, above, and Angie Craig flipped suburban House seats, but Craig faced a more closely divided district. (The Minnesota Star Tribune)