|Al Jazeera's Kimberly Halket reports from Washington DC on Obama's immigration reform
President Barack Obama has issued an impassioned call for immigration reform in a speech at the US-Mexican border, sending a message to Hispanics whose votes he needs to win re-election next year.
Obama, whose 2012 chances depend largely on the health of the US economy, made the case that immigration reform would have economic benefits for the middle class and for businesses, while also improving national security.
Speaking on Tuesday, he said he wanted to provide illegal immigrants with a path to citizenship - which he said would benefit the US economy.
"One way to strengthen the middle class in America is to reform the immigration system, so that there is no longer a massive underground economy that exploits a cheap source of labour while depressing wages for everybody else," Obama said.
"That's why immigration reform is an economic imperative."
Tightening immigration laws - and opposing the idea of giving "amnesty" to those who broke the law sneaking into the country - has become a rallying cry for many Republicans who want a clampdown to keep drug crime from crossing the border.
Major overhaul unlikely
Obama sought to portray Republicans' resistance to fixing problems with the US immigration system as evidence they were hostile to the interests of Latino voters.
But he offered no concrete policy initiatives or timelines for introducing broad legislation, underscoring the fact that he is unlikely to advance any major overhaul before the 2012 presidential election.
Efforts to tighten security along the US-Mexican border, including a $600 million bill signed in August to hire 1,500 border patrol agents, customs inspectors and law enforcement officials, have already had an impact, the president stressed.
"The truth is, the measures we've put in place are getting results. Over the past two and a half years, we've seized 31 per cent more drugs, 75 per cent more currency, 64 per cent more weapons than ever before," Obama said.
But Obama said opponents of immigration would never be happy, despite any tight controls that have been put in place.
"They wanted a fence," he said, to boos from the crowd, speaking in shirt sleeves on a hot, sunny day at a park within sight of the border.
"Well, that fence is now basically complete. Maybe they'll need a moat. Maybe they'll want alligators in the moat," he said.