Barack Obama has described lack of immigration reform as the biggest failure of his presidency, but blamed his inability to legalise millions of undocumented immigrants on what he implicitly admitted was another failure – the collapse of his attempts at compromise and consensus with Congress and the realisation that he "cannot change Washington from the inside".
Obama was repeatedly pressed on immigration by a mostly Latino audience in an interview on the Spanish-language Univision TV station in Miami. He was forced to defend his record on deportations of illegal immigrants and to deny that his order in July allowing about 1.7 million young undocumented migrants to obtain work permits was an election ploy.
Obama was also accused of breaking a promise, made during the 2008 presidential election campaign, to permit a path to citizenship or residency for many undocumented immigrants during his first year in office.
Asked later in the interview what the greatest failure of his presidency has been, Obama returned to the topic.
"My biggest failure so far is [that] we haven't gotten comprehensive immigration reform done," the president said. "But it's not for lack of trying or desire – and I'm confident that we're going to accomplish that."
Obama denied he had broken his promise and went on to blame his inability "to change the tone in Washington" for the lack of an immigration reform law. He said that as soon as he came to power, Republicans conspired to block him.
Obama said he could not find a single Republican to work with him on immigration legislation. He said he had been "naive".
"The most important lesson I've learned is that you can't change Washington from the inside; you can only change it from the outside. That's how I got elected and that's how the big accomplishments like healthcare got done, was because we mobilised the American people to speak out," he said.
"Something I'd really like to concentrate on in my second term is being in a much more constant conversation with the American people so that they can put pressure on Congress to help move some of these issues forward."
Opinion polls show Latino voters to be twice as likely to vote for Obama as Romney, but many votes are up for grabs in some battleground states such as Florida.
The Republicans, keen to go on the offensive after a torrid two weeks, immediately pounced on the remarks, with Mitt Romney repeatedly mentioning them during a speech in Sarasota. Claiming that the president had broken a promise made in 2008, Romney said: "His slogan was: 'Yes we can'. Now it's: 'No I can't'."
On Twitter, Reince Priebus, chairman of the Republican National Committee, wrote: "Between no immigration reform and can't change DC from the inside, seems like Obama just admitted his 08 campaign was garbage."
The Univision audience questioned Obama on issues that rarely get much of an airing in the US English-language media, such as combating Mexico's drug cartels.
But the primary focus was on immigration, a source of considerable concern in Hispanic communities where families often have relatives or friends who are in the US illegally.
Obama was pressed on why there has been a rise in deportations of illegal immigrants under his presidency. He said that it was in part because Congress put more money into enforcing border controls. Nonetheless, he said the target of deportation is not "hard-working families" and those with long ties to the US.
"More than half of our enforcement now is directed at people with criminal records. Of the remaining half, about two-thirds are people who are typically apprehended close to the border. So these are not people who have long standing roots," he said.
But he added: "We still ultimately have to change the laws."
Although Obama faced strong scepticism at times, he appeared to emerge in better shape than his Republican rival, after Romney a similar appearance on Wednesday on Univision, a principal source of news for a large number of Latino voters.
Romney was accused of evading questions about whether he would deport undocumented aliens, including the young people Obama ordered should be permitted to stay. Eventually an exasperated Romney said: "We're not going to round up 12 million people, that includes kids and parents, and have them all deported."
Romney said that as president he would find a "permanent solution" to an immigration system that has "been broken for years". This included temporary work permits and permanent residency cards to people with advanced qualifications.
But he repeatedly refused to say whether he would overturn Obama's order permitting young illegal immigrants without a criminal record to remain in the US and obtain a work permit.
"These kids deserve something better than temporary – they deserve a permanent position," Romney said without offering a specific alternative.
Earlier this year, Romney said he favoured policies to promote "self-deportation" of illegal immigrants, but he downplayed that on Wednesday.
Rommey's attempt to woo Hispanic voters was further damaged on Thursday with the emergence of a clip from a video of a Romney fundraiser in which he said that illegal immigrants generally "have no skill or experience".
"Gosh, I'd love to bring in more legal immigrants that have skill and knowledge. I'd like to staple a green card to every PhD in the world and say, 'Come to America, we want you here.' Instead, we make it hard for people who get educated here or elsewhere to make this their home," he said.
"Unless, of course, you have no skill or experience, in which case you're welcome to cross the border and stay here for the rest of your life. It's very strange."
Obama took the opportunity to take a jab at Romney over other parts of the fundraiser video which has been leaked in recent days - particularly Romney's assertion that the half of American voters who support Obama pay no income tax, rely on the government for handouts and think of themselves as victims.
Obama said Romney is out of touch.
"When you express an attitude that half the country considers itself victims, that somehow they want to be dependent on government, my thinking is maybe you haven't gotten around a lot,'" he said.
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