Realignment and transformation throughout our nation’s political landscape is not new. Our country will always be divided over who gets the political upper hand and the fight to keep it. With today’s polarization approaching Civil War levels, the division is no longer regional (North vs. South). It is more political (red vs. blue) but remains divided by culture, race, and class. At one time, the Democrats were the conservatives, and the Republicans were the liberals. It is unlikely we will ever see the two parties flip again in ideology, but the internal political transformation on the state level will always take place.

Whenever I think of the Democratic Party, I see it as a big tent party of political inclusion. It generally welcomes a broad spectrum of views and beliefs, reflecting a nation of people with diverse backgrounds, experiences, and cultures. The Democrats, with its broad coalition of movements, face a greater challenge than Republicans in keeping their big tent intact from one election to another.

Since people don’t like to be taken for granted, the Democratic Party must work hard and focus on expanding the big tent and keeping it unified. Therefore, Democrats should have listened more to Tom Vilsack when he sounded the alarm as Agriculture Secretary in the Obama administration. Mr. Vilsack grew frustrated with a culture in Washington that often ignored rural America’s struggles.

“I just sometimes think rural America is a forgotten place,” he often said.

The fact that many white, working-class voters turned decisively to the former reality TV star after supporting President Obama in 2008 and 2012 played a big part in electing Donald Trump as president. Before Trump’s surprising victory, Mr. Vilsack complained loud and often that the Democratic Party had given up competing in large areas of the country that were necessary to win Senate seats, governor’s races, and state legislatures.

Before Mr. Vilsack became Agriculture Secretary, he served two terms as governor of Iowa, which is 95% white. His eight years as governor should have been the national blueprint for the Democratic Party to follow in addressing the isolation of white working-class voters in rural America—now, rural America has become the heart of Trump’s MAGA movement.

When Mr. Vilsack won his longshot race for governor in 1998, it was the first time Iowa had elected a Democrat in 32 years. In eight years, he transformed the state’s political landscape.

“I personally took over managing legislative races,” Mr. Vilsack said. “We won the House and the Senate, and we had three of the five members of Congress.”

His success was a boon for President Obama, whose 2008 victory in Iowa proved that he could attract the support of white Midwestern voters.

As the party of political inclusion, the Democrats were deaf to Mr. Vilsack’s warnings.

All the political gains in Iowa made at the state and federal levels and in presidential elections are now erased. Today in Iowa, Republicans dominate every aspect of state government while controlling both U.S. Senate seats and three of the four U.S. House seats.

Today, Florida is in the midst of its own political transformation by building on a trend over the last decade that has pushed the state further to the right. Miami-Dade County has long been a Democratic stronghold in Florida. If

Republican success in expanding their support with Hispanic voters continues to gain momentum, it would likely take Florida out of play entirely for Democrats in future presidential elections.

As the Democrat’s political base shrinks in Florida with a growing number of Hispanic voters flipping to the Republicans, the Democratic Party’s dependence on the Black vote becomes even more critical with future elections. No one likes to be taken for granted. As rural voters nationally felt ignored and taken for granted, Hispanic voters in certain areas of the nation are feeling the same way.

The Democrats cannot afford to make the same mistake with Black voters.

The writer is the founder of the faith-based organization TRB: The Reconciled Body and author of “God Bless Our Divided America.”