This week’s special election for a state Senate seat represented a more than 40-point swing between the two parties in just two years.

Democratic State Representative Lauren Arthur beat Republican State Representative Kevin Corlew by 19 points on the heels of Republican former Senator Ryan Silvey’s landslide 22-point reelection in 2016.

The geographic area of Senate District 17 in suburban Kansas City’s Clay County is known for its swing voting.

Both Arthur and Corlew ran as moderates.  They clashed on issues such as abortion and taxes but voted together in support of labor as the district is home to the Claycomo Ford plant which employs roughly 7,500 union workers.

Silvey, who was appointed to a seat on the state Public Service Commission in January, also backed labor interests.

Democratic strategist Jack Cardetti thinks Corlew tried to cloud his Republican Party affiliation in the election.  “I think he clearly tried to run as a Democratic light, a diet Democrat version, being pro-labor and being against his party on a couple of different issues like that” said Cardetti.  “Clearly voters saw right through that.”

Cardetti doesn’t think the various scandals surrounding recently resigned Republican Governor Eric Greitens had an oversized bearing on the election.

Missouri Republican Party Executive Director Sam Cooper agrees.  He thinks the result had more to do with voting trends in the district and the timing of the election when turnout is light.  “This was a June special election in a seat that is increasingly moving Democrat, and the numbers back that up,” said Cooper.

The Missouri race has garnered national attention as it joins a growing list of elections in states around the country in which seats have flipped from Republican to Democrat in districts where President Donald Trump prevailed.

The election analysis group Decision Desk issued a 2016 breakdown this week of the 17th District which reflected a five-point victory by President Trump.

It also showed that Democrats Jason Kander and Chris Koster carried the U.S. Senate and governor’s races in the district, by 11 and 5 points respectively.  Both candidates lost the election statewide.

Cooper thinks the root cause of the Republican loss in the special election can be traced to demographic trends.  “What I think it is is more younger folks moving up from the city into the Northland,” Cooper said.  “And that demographic usually tends to swing a little bit to the left.”

Looking ahead to November, Cardetti thinks Tuesday’s election should worry Republicans.  It’s the state’s second suburban voting district to switch from the GOP to Democrats in the past year.  Representative Mike Revis of Fenton carried a special election last fall in the 97th House District, which sits in Jefferson and St. Louis Counties.

Cardetti thinks the suburban counties, which have trended toward Democrats lately, will decide the outcome of November’s U.S. Senate race.  “Your Clay County, Platte County, Cass County – those are the type of places that really swing statewide elections,” Cardetti said.  “And if you don’t perform well there then you’re not going to win Missouri.”

State Republicans are taking heart in Morning Consult’s “Midterm Wave Watcher” that came out Wednesday.  According to the market research and online survey organization, Democrat Claire McCaskill has the weakest approval rating of the 10 U.S. Senators facing a competitive race this year – 38% approve vs. 52% disapprove.

Cooper points out that President Trump has the highest approval rating of any Republican among Missourians.  He says McCaskill has fought against the President on almost every position she’s taken.

“I’d be hard-pressed to find a major piece of the President’s agenda that she’s supported,” Cooper said.  “From Neil Gorsuch (Supreme Court nominee) to tax cuts, she’s been on the wrong side of every single one of those issues.”

Still, the Real Clear Politics average of polls shows McCaskill with a slight lead over her most likely Republican opponent, state Attorney General Josh Hawley.  She had a four-point lead in a Missouri Scout poll from last month.

Cardetti thinks Tuesday’s special election is a leading indicator of what’s likely to take place in November.

“Democrats will be running with the wind at their back,” said Cardetti.  “Republicans will be running politically with the wind in their face because suburban voters right now, whether it’s Clay County, Jefferson County, are abandoning Republicans right and left.”