JENKS, Okla. -- Someone in the rafters shouted: "Donald Trump has small hands!"

"We're not talking about that today," Sen. Marco Rubio (R-Fla.) said in response. "It was fun while it lasted."

Fighting a raspy voice after an intense day of campaigning, Rubio concluded a four-state trek Monday night by once again attacking Trump, the GOP front-runner, by largely avoiding petty zingers he's employed in recent days.

He still called Trump "a con artist" but there was little talk of the businessman's small hands, or spray tan, or his large private plane. Instead, Rubio warned that the 2016 presidential election "is a referendum on our identity as a nation and as a people."

The sudden shift in tone -- and admission he wasn't going to get personal -- came as party leaders and many Rubio supporters expressed concern in the last day with the senator's use of Trump-style taunts focused on his rival's personality and personal appearance.

Rubio told at least 2,000 people -- though the campaign said it was closer to 5,000 -- packed into a steamy high school gymnasium that he decided to go after Trump in last week's presidential debate and intensify his attacks after learning details of Trump University, one of the businessman's failed enterprises that cost students tens of thousands of dollars and resulted in little in return. He said several people who enrolled in the institution have contacted his campaign with stories about how they lost tens of thousands of dollars after Trump promised them an education.

In the debate, "I stood up for you. I stood up for the conservative movement," he said. "I stood up for the party of Lincoln and of Reagan."

"A vote for Donald Trump tomorrow is literally a vote for Hillary Clinton in November," he warned later.

Oklahoma is one of 11 states voting on Super Tuesday, which will reward nearly 600 delegates to GOP candidates on a proportional basis. Polls in the Sooner State give Trump a wide lead, with Rubio and Texas Sen. Ted Cruz fighting to place second. That's much the same in many of the other states in play on Tuesday, including Virginia and Georgia.

Jenks embodies perfectly the kind of community packed with the kind of voters the Rubio campaign thinks it can draw. It's a suburb of Tulsa, packed with younger, middle-class Republican families. Several younger parents had young infants with them at the rally. The high school where Rubio held his event sits on a large campus with a football stadium next door. The high school football team has won the state championship 15 times since 1979.

Many people in the crowd waited more than 90 minutes for Rubio to arrive from Oklahoma City. The event in Tulsa included appearances by former Louisiana governor Bobby Jindal and former Oklahoma senator Tom Coburn, who is suffering from cancer and has rarely appeared in public since retiring in 2015.

Rubio is "going to lead us to higher aspirations. He’s going to call on us to do something greater," Coburn told the crowd. "There’s no problem in front of this country that can’t be solved."

Cecilia Manriquez, 57, said she has supported Rubio since he launched his presidential campaign last year. An immigrant from Venezuela, she said the senator "knows what communism can do to a country. And I don’t want our country to go into the hands of people who would do what happened in my former country.”

She called Trump "extremely self-centered and when [candidates] are that way, they don’t listen to others. Trump wants the presidency to satisfy his own pride.”

Deanna McQuay, 36, brought her three children from Skiatook, Okla. to see Rubio for a second time -- they saw him in Oklahoma City last week.

She briefly considered voting for former neurosurgeon Ben Carson, but she said Rubio "seems like a nice person who can articulate the conservative message."

As Rubio concluded the rally, most supporters rushed for the exits. But hundreds of admirers lingered in hopes of shaking his hand or taking a selfie. The David Guetta song, "Yesterday," blasted overhead.

"It seems like trouble's on the way. I'm gonna live, I'm gonna love," the song goes. "Hey, hey, what you say?
I've got no use for yesterday."