Ohio is crucial in the 2016 general election, yet Republican nominee Donald Trump continues to look into his rearview mirror and throw trash out his window onto Ohio’s popular GOP governor, John Kasich, whom he already defeated in the primaries.

After reportedly offering Kasich the vice presidency (which Kasich rejected, along with refusing to endorse the GOP nominee), Trump has reportedly threatened to set up one or two super PACs and spend $20 million to attack Kasich and Sen. Ted Cruz of Texas.

That ain’t going to be easy. In his most recent run for governor, the politically skilled Kasich got 64 percent of the vote. In the March 15 Republican presidential primary, he won the state handily with 47 percent of the vote, to 36 percent for Trump. On the Democratic side, former Secretary of State Hillary Clinton carried Ohio with 57 percent of the vote.

During the chaotic Republican convention in Cleveland, Trump’s shady manager Paul Manafort, with ties to the ousted pro-Putin dictator in Ukraine, found time to belittle Kasich, the man who could determine Trump’s fate in Ohio and thus perhaps the entire election. He did it despite the fact that Ohio has 18 electoral votes (out of 270 needed to win); only four states have more.

Governors have enormous power within their borders. In a state of nearly 12 million residents, Kasich controls thousands of jobs, workers and billions in funds for state, county and local governments, as well as private sector contracts. A governor is the most powerful elected official in any state. What he says goes.

Kasich has been a favorite with the political press for his bluntness, accessibility and candor. On Saturday, Kasich joined the bipartisan condemnation of Trump for criticizing the parents of a Muslim soldier who died in Iraq. Trump showed no remorse, no sympathy, no respect for their loss. Khizr Khan came to America from Pakistan, going from abject poverty to graduating from Harvard University. At the Democratic National Convention, he chastised Trump for his calling for a wholesale ban on Muslims, and asked plaintively if Trump had even read the Constitution; he offered to lend him his pocket version, which he displayed.

Fox News viewers were never shown the father’s dignified speech with his wife Gazala, too distraught to speak, by his side. Too gripping, too revealing, apparently. After Trump crudely attacked the couple, an angry Kasich tweeted, “There's only one way to talk about Gold Star parents: with honor and respect.”

One more reason Kasich would like to see Trump fail this fall: Kasich himself may decide to run for president in 2020.

As for this year, he says Trump will have trouble winning Ohio. The state is a key element in Trump’s industrial Midwest strategy. Kasich vows, “There’s no way that I’m going to vote for Hillary Clinton.” The latest Real Clear Politics average of polls of Ohio shows Clinton barely ahead, 42.6 percent to 41.8 percent for Trump.

The governor may need to change his mind.