The suburbs are an important battleground and comprise a range of communities accounting for half of all voters

President Trump has targeted one type of community consistently, as his campaign enters the home stretch toward November: He wants to talk to and about the suburbs.He has said on the campaign trail that crime is out of control in cities, the fault, he says, of Democrats and which would worsen if former Vice President Joe Biden wins the White House. Mr. Trump often addresses that message to voters who live outside the urban centers, and he tells them that more low-income residents would move to the suburbs under Democratic housing policies.Why would Suburban Women vote for Biden and the Democrats when Democrat run cities are now rampant with crimewhich could easily spread to the suburbs, he said on Twitter last month.
If the Left gains power, they will demolish the suburbs, he said in accepting the GOP presidential nomination last month.
Mr. Biden hasnt focused as directly on the suburbs in public remarks. However, he has said that Mr. Trump is trying to scare the hell out of the suburbs.
Mr. Trumps emphasis on the suburbs isnt surprising. With urban voters backing Democrats and rural voters increasingly supporting Republicans, the suburbs are an important battleground. But the term applies to a range of communities, and Mr. Trumps messages arent likely to get the same reception in every suburb.
Half of voters live in the suburbs, Wall Street Journal/NBC News surveys and presidential exit polls show. Some suburban communities are more diverse than the nation as a whole and have higher levels of educational attainment, while others are less diverse and less wealthy.
Here are three key points to consider in thinking about the political profile of suburbs.
Density, diversity and education levels make a difference.
Communities that are densely populated, racially diverse and have high educational attainment levels tend to lean Democratic. Communities that are largely rural, white and have relatively few college graduates tend to lean Republican.
The American Communities Project at George Washington University uses these and other markersincluding demographic, economic and religious qualitiesto divide counties into groups. The biggest suburban groups are urban suburbs, exurbs and blue-collar suburbs.
Urban-suburb counties increasingly look like cities in terms of racial and economic diversity and density. They are less non-Hispanic white than the nation as a whole, and they exceed the national average for residents with bachelors degrees. Median household incomes are also high, at roughly $70,000, compared with $60,000 nationally. Like the cities they surround, these communities are heavily Democratic. One example is Montgomery County, Md., near Washington, D.C.
Exurban counties are far more rural and less racially and ethnically diverse, but college graduates are still plentiful, and median household incomes are high, at about $65,000. An example is Douglas County, Colo., outside Denver.
Exurbs lean Republican in their vote choice. Mr. Trump won these counties by about 17 points in 2016. WSJ/NBC News polling this year shows him with a smaller 7-point lead there.
A third type of county, the blue-collar suburbs, tends to have more manufacturing workers than the nation as a whole. They are densely populated but not very racially or ethnically diverse, and bachelors degrees are scarcer. Lake County, Ohio, not far from Cleveland, is a good example.
These counties are important to watch in the last weeks of the election because they provided lopsided vote margins for Mr. Trump that helped him win Pennsylvania, Wisconsin and Michigan. WSJ/NBC News polls show the race is essentially tied in these counties this year.
Suburbs are on different political journeys.
Blue-collar suburbs as a group had been trending toward Republicans in recent elections. They narrowly backed Barack Obama in 2008, then swung narrowly to the GOP in 2012 before moving heavily behind Mr. Trump, backing him by a margin of 13 points.
The wealthier urban suburbs, by contrast, stayed strongly Democratic, voting for Mr. Obama by 19 points in 2008 and for Democratic nominee Hillary Clinton by 18 points in 2016. In the combined Wall Street Journal/NBC News polls this year, Mr. Biden leads in these counties by about 25 points.
In some states, these counties are right next to each other. Outside Detroit, Mr. Obama won Oakland County, a wealthy urban suburb, by about 14 points in 2008 and neighboring Macomb County, a blue-collar suburb, by about ninea difference of five points.
Eight years later, Mrs. Clinton won Oakland by about eight points, but Mr. Trump carried Macomb by almost 12 pointsa gap of roughly 20 percentage points.
The suburbs are changing.
The population of urban suburb Fairfax County, Va., is 50% non-Hispanic white today, down from 64% in 2000. In the same period, its Asian population rose to 20% from 13%. A suburb of Washington, Fairfax County has gone from a closely contested battleground that Republican George W. Bush narrowly won to a solidly Democratic county that Mrs. Clinton carried by more than 35 percentage points.
Population changes have had different political ramifications in other kinds of suburban areas.
The population of Delaware County, Ohio, an exurb north of Columbus, grew by 84% between 2000 and 2018, and the share of college graduates grew by more than 13 percentage points, to more than 54%. In that time, it remained a Republican stronghold, but Democrats made gains. In 2016, Mr. Trump won the county by about 16 percentage points, while Republican Mitt Romney carried it by about 23 points four years earlier.
In Beaver County, Pa., a blue-collar suburb to the west of Pittsburgh, the population has shrunk by more than 9 percentage points since 2000 and has undergone little racial or ethnic change. In 2000, 93% of the population was white and non-Hispanic. Today, the figure is roughly 89%.
The county is one of many in the region to grow more Republican. Mr. Trump won 57% of the vote there and had a margin of victory of more than 15,000 votes. He carried Pennsylvania by only 44,000 votes.
Arizona has been reliably Republican since 1996 and Minnesota reliably Democratic since 1972. But as WSJs Gerald F. Seib explains, both states are in play for the 2020 election. Photos: Stephen Maturen/Getty Images
Write to Dante Chinni at Dante.Chinni@wsj.com and Aaron Zitner at Aaron.Zitner@dowjones.com
SHARE YOUR THOUGHTS
What issues do you think will figure most prominently with the different suburban voters in November? Join the conversation below.
Copyright ©2020 Dow Jones & Company, Inc. All Rights Reserved. 87990cbe856818d5eddac44c7b1cdeb8