JOHNSTON, Iowa — Sen. Marco Rubio (R-Fla.) criticized Donald Trump's "theatrics" the day after Trump said he would not participate in Thursday night's Republican presidential debate, and he lumped Trump together with Sen. Ted Cruz (R-Tex.) in an effort to portray himself as a serious alternative to the two front-runners.

"America is heading the wrong direction, and people are right to be angry about it. But it’s not enough just to be angry," Rubio said in a written statement sent Wednesday by Rubio spokesman Alex Conant in response to an e-mail seeking comment on Trump's decision. "The next president has to have a real plan to turn the page on Obama and his disastrous policies, and they have to be willing and able to sell that plan to the American people. That’s why these debates are so important."

Rubio added: "These kinds [of] theatrics by Ted Cruz and Donald Trump are an entertaining sideshow, but they have nothing to do with defeating Hillary Clinton. I’m going to stay focused on uniting the Republican Party so we can defeat Hillary Clinton and turn the page on eight years of liberal failure. We don’t have time for these kinds of distractions."

Conant didn't immediately respond to a question about what Cruz "theatrics" Rubio was seeking to highlight. Cruz plans to participate in the debate.

The statement comes as Rubio is pitching himself in the final days before the Iowa caucuses as a more electable alternative to Trump and Cruz. At successive event, he has tried to get his crowds to envision a Clinton or Bernie Sanders presidency, which he says would uphold policies implemented by President Obama that conservatives find most abhorrent. The intent is to draw their focus to winning the general election and to raise doubts about whether Cruz and Trump are up to that task.

Thus, the effort to loop Cruz into his statement about Trump.

Polls show Cruz and Trump leading the field in Iowa, with Rubio sitting in a distant third. Senior Rubio strategist Todd Harris told reporters Tuesday that Trump's decision to forgo the debate will probably mean more attacks against Rubio.

"It probably means the target on our back just got a little bit bigger, but at the same time it means that we're going to have a lot more opportunity for Marco to get his message out," Harris said.

A look back at the clash between the Fox News anchor and presidential candidate that started with an earlier debate in August 2015. (Sarah Parnass/The Washington Post)