WARREN, Mich. — Donald Trump holds a solid lead in two new polls of Michigan Republicans on the eve of a primary that has often played a key role in GOP presidential races. In one survey, by CBS News, Trump is at 39 percent, versus 24 percent for Ted Cruz, 16 percent for Marco Rubio, and 15 percent for John Kasich. In another, by NBC News and the Wall Street Journal, Trump is at 41 percent, versus 22 percent for Cruz, 17 percent for Rubio and 13 percent for Kasich.

NBC found Trump leading among men and women, Republicans and independents, conservatives and moderates. And 61 percent of likely GOP voters said they strongly support their candidate, while just 12 percent said they are likely to change their mind.

The Michigan Republican contest is an open primary, meaning the Republicans, independents, and even some Democrats who have made up Trump's support in other states will be free to cast ballots. But on Trump's only day of campaigning here, last Friday, the majority of Michiganders who came to see him were Republican voters, many of them longtime Republican voters. They go way back with the GOP, and they seemed to have particularly intense feelings about their party, its officials, and the conservative thought leaders who they see as trying to destroy Trump's candidacy. The short version is, they've had it with the whole bunch.

Trump appeared at Macomb Community College, in Macomb County, home of the storied Democratic voters who helped put Ronald Reagan in the White House in the 1980s. Trump took the stage just 12 hours after a contentious Republican debate in Detroit, and after 2012 Republican nominee Mitt Romney attacked Trump in a widely-discussed speech.

This is Michigan, Romney's home state, where Romney's father was governor, where his niece Ronna Romney McDaniel chairs the state Republican party, and where the Romney name is still held in high regard. I didn't talk to anyone who hadn't voted for Mitt Romney in 2012. And I didn't talk to anyone who approved of Romney's decision to go after Trump.

"I was very upset about that," said Bill Heald, of Oak Park. "I voted for Romney. He had no business saying anything … If you were going to get into it, get into it earlier. Don't start that crap right now."

"I thought it was a very low blow," said Mike Morris, of Brighton.

"He was out of place," said Paul Lee, of Sterling Heights.

"He shouldn't have done what he did," said Martha Theis, also of Sterling Heights. "I don't think that he did that on his own. I think the party put him up to it."

"I personally didn't like it," said Rani Escamilla, of Sterling Heights. "He ran, I voted for him, now he's done, stay away, let's move on."

"I think it's utterly disgraceful that the GOP is putting up everything they can to stop Trump," said Rani's friend Deanna Schwarz, of Wolverine Lake. "I think what [Romney] said was disgraceful, and I think it was the words of the GOP. It may not have been his words, because when he ran against Obama, he didn't talk that tough. So I don't think they were his words."

"I campaigned for Romney," said Coleen McDonald, of Troy. "I live in the same community as Ronna. He didn't have the fight in his belly. Who's going to fight for us? … No matter what happens, I'm going to vote for Donald Trump."

The crowd, estimated at 4,000, was ready to rock and roll — at 9 o'clock on an icy Friday morning. They cheered Trump's discussion of Mexico, his denunciations of former Mexican President Vicente Fox, and at one point broke into a long, spontaneous chant of "Build the wall! Build the wall! Build the wall! Build the wall! Build the wall!"

"We're are not going to play games," Trump said, which was exactly what they wanted to hear.

"What's happened to you people is disgraceful," Trump said of the auto industry's decline. "Mexico is becoming the car capital of the world, whether you like it or not, and we're going to turn that around … In a couple of years, you'll go home to your wife and home to your husband and say, 'Darling, I have so many job opportunities, I'm going absolutely crazy.' As opposed to now …"

Trump instinctively sensed that he could bash Romney in Romney's home state with no consequences at all. "This guy Romney came out yesterday," Trump began, which brought on lots and lots of boos. "The hatred he has, the jealousy, the hatred, it's hard to believe."

More boos. "You guys should like him, right?" Trump said. Still more boos.

'Deport Romney!" yelled a man in the crowd.

"Thank you," said Trump.

"Loser," yelled a woman near me.

The anger and frustration did not stop with political figures. A number of people complained to me about conservative media, which they believe hasn't treated Trump fairly. "I'm a National Review reader," said a man who walked up to me during Trump's speech. "I can't even look at the site anymore. It looks like Salon. Nine stories tearing [Trump] apart, man. I don't get it."

In many of Trump's victories this year, commentators have noted that late-deciding voters have chosen another candidate, either Marco Rubio earlier in the campaign, or Ted Cruz more recently. Trump would then "underperform" poll estimates, while still winning. That inevitably led to the suggestion that GOP voters were changing their minds and that Trump was fading. Late deciders moved away from Trump in Iowa on Feb. 1 and in South Carolina on Feb. 20 and in the Super Tuesday states on March 1, and yet Trump has still won the majority of contests so far.

I asked Matthew Dowd, the former George W. Bush strategist who early on recognized the power and reach of Trump's appeal, for an explanation. "It looks like in every single state voting thus far, Trump voters have made up their minds long before Election Day," Dowd told me via email. "I don't see much evidence of someone who was a Trump voter switching at the last minute."

What's taking place, Dowd explained, is that "undecided voters are solidly against Trump, but just haven't settled on another candidate yet, and make up their mind in last days or on Election Day." The good news for Trump is that his voters are solid. The bad news, Dowd continued, is that "Trump's behavior and the conduct of his campaign are limiting him on expanding to a more dominant position. Because of his flaws, Trump is preventing himself from running away with this. If he could somehow become a better, more expansive leader, he would gather momentum and could not be stopped. The attacks on Trump haven't hurt Trump. Trump has hurt Trump in not picking up speed faster."

Now, Trump is leading in Michigan. If the pattern Dowd described holds true, Trump might be headed to a victory that, like some of his others, is a bit less than the polls predicted. But there's no doubt he is connecting with many, many unhappy Republicans in Michigan. They feel their party has let them down, and is still letting them down by trying to sink Trump. Their way of fighting back is to cast a Trump vote on Tuesday.