President Obama and Hillary Clinton have intensified attacks on Republican presidential front-runner Donald Trump, accusing him of manipulating voters’ “fear and ignorance” and using anti-Muslim rhetoric that helps recruit Islamic State terrorists — jabs that appear to be energizing his supporters and strengthening his campaign.
But campaign strategists say the attacks are not aimed at knocking down Mr. Trump. Instead, the smears are part of a calculated ploy by Democrats who want to help him win because they are convinced the billionaire businessman will lose in the general election.
“It definitely makes my allegiance to Donald Trump much greater,” Jeff Moorman, a Trump campaign supporter in Iowa, said after hearing the insults hurled at his candidate.
That is exactly the reaction Democrats want, said Republican campaign consultant Ryan Williams.
“It is a calculated effort on the Democrats’ part to elevate Trump. They clearly want Trump to be the nominee because they think they can beat him easily,” said Mr. Williams, who worked for the campaign of 2012 Republican nominee Mitt Romney.
“Attacks from Democrats like Hillary Clinton and Barack Obama do nothing but energize Donald Trump’s supporters, and I suspect both Clinton and Obama are smart enough to realize that,” he said.
In a head-to-head matchup, the RealClearPolitics average of national polls show Mrs. Clinton beating Mr. Trump by an average of 6 percentage points, significantly higher than other Republicans such as Sen. Ted Cruz of Texas and Sen. Marco Rubio of Florida, who trail Mrs. Clinton by 1.5 percentage points and 2.5 percentage points, respectively. All the other Republican contenders fare better in matchups with Mrs. Clinton than Mr. Trump in the average of national polls.
Mr. Trump has been a target for Democrats’ attacks throughout the campaign. But the attacks have grown sharper as he defied predictions that his unconventional campaign would flare out and remained atop most polls.
Taylor Budowich, a national spokesman for the Tea Party Express, suspects Mr. Obama and Mrs. Clinton were trying to stir up conservative voters. But he said the scheme likely would backfire, pushing a wave of Republican voters to the polls.
“Sometimes a lot of these political consultants and political strategists get too smart for their own good,” he said. “In trying to control the outcome of an election, they end up getting the exact opposite outcome than what they wanted.”
Mrs. Clinton, the Democratic front-runner and the odds-on favorite to win the nomination, repeatedly hammered Mr. Trump during a Democratic candidates debate Saturday, saying his call for a temporary ban on Muslims entering the U.S. “fans the flames of radicalization.”
“He is becoming ISIS’ best recruiter. They are going to people showing videos of Donald Trump insulting Islam and Muslims in order to recruit more radical jihadists,” Mrs. Clinton said at the debate in New Hampshire.
Mr. Trump demanded an apology Monday during an interview on NBC’s “Today” show.
“I will demand an apology from Hillary. She should apologize,” he said. “She lies about emails, she lies about Whitewater, she lies about everything. She will be a disaster as president of the United States.”
Mr. Trump said that saying he is being used in videos produced by the Islamic State, also known as ISIS, was another lie from the former secretary of state.
“You’re talking about people dying. You’re talking about making up tapes and videos which don’t exist,” he said.
An exhaustive search for Islamic State videos and online postings did not produce evidence that Mr. Trump was being used as a recruitment tool, so the fact-checking organization Politifact rated Mrs. Clinton’s statement “false.”
Still, Clinton campaign spokesman Brian Fallon said an apology was not in order.
“Hillary Clinton will not be apologizing to Donald Trump for correctly pointing out how his hateful rhetoric only helps ISIS recruit more terrorists,” he said.
Meanwhile, Mr. Obama took a swipe at Mr. Trump and the candidate’s supporters.
He said Mr. Trump was exploiting the “anger, frustration, fear” of blue-collar men who are threatened by the rise of multiculturalism and a technology-based economy.
“I think somebody like Mr. Trump is taking advantage of that. That’s what he’s exploiting during the course of his campaign,” the president said in an interview with NPR.
Mr. Obama took a similar swipe at Mr. Trump and his supporters in a fundraising email for the Democratic National Committee.
In the email, the president said that because of his race and his unusual name, he had grown accustomed to being questioned about his religion, place of birth and “even whether I love this country.”
“I always dismissed that kind of talk, but I’ve also learned to listen closely when a conversation starts to lean on fear and ignorance,” he wrote. “So I pay attention when I hear the Republican frontrunner for president call for a ban on Muslims entering this country. And when their other candidates say we should only admit Christian refugees, not Muslims, or that there should be a religious test to determine which people fleeing a war-torn country can enter ours.”
Mr. Williams said the attacks that fire up Mr. Trump’s conservative supporters also motivate liberals to open their wallets.
“Trump, for better or worse, is the kind of candidate who elicits reactions on both sides,” he said. “People can use a lightning rod like Trump in politics to their advantage to accomplish what they are looking for.”