Here's a look at statements from both President Obama and Mitt Romney and how they match up with the facts:
Obama: "We should have passed the DREAM Act a long time ago. It was written by members of both parties. When it came up for a vote a year and a half ago, Republicans in Congress blocked it. The bill hadn't changed. The need hadn't changed. The only thing that had changed was politics."
The facts: Five Senate Democrats voted against sending the DREAM Act to the floor for full consideration. The bill would have created a path to citizenship for many young illegal immigrants brought to the United States as children.
Romney: "As president, I'd reallocate green cards to those seeking to keep their families under one roof. And we will exempt from caps the spouses and minor children of legal permanent residents. And we will eliminate other forms of bureaucratic red tape that keep families from being together. ... And if you get an advanced degree here, we want you to stay here. So I'd staple a green card to the diploma of someone who gets an advanced degree in America."
The facts: It's unclear whether Romney would have the authority if elected president to change the way green cards are issued, or whether he would need help from Congress. It is Congress that sets the annual limits for visas for foreigners who have advanced degrees in certain fields of science, math and other professions. Lately, Republicans and groups representing U.S. workers have blocked legislative attempts to increase those limits.
Romney: "I will work with states and employers to update our temporary worker visa program so that it meets our economic needs."
The facts: Temporary and seasonal workers are considered a necessity for the U.S. agriculture industry, but importing legal workers has proved difficult. Republicans have repeatedly said that any immigration bill offering a path to legalization would not win their support.
Romney: "We should field enough Border Patrol agents, complete a high-tech fence and implement an improved exit verification system."
The facts: Romney's plans don't take notice of what's already been done, including record-high staffing levels along the border and the failure of a Bush-era virtual fence plan.
The Border Patrol has more than 18,500 agents working on the southern border. In the year budget ending last September, agents apprehended about 340,000 illegal immigrants, the fewest in nearly 40 years -- an average of 18 apprehensions per agent. The decrease in apprehensions has been linked to a weak economy producing fewer U.S. jobs and to more law enforcement agents and technology along the border.
A planned virtual fence was started, but then scrapped by the Obama administration in 2010 after the project was deemed a failure. About 53 miles of virtual fencing is in place, at a cost of about $1 billion. An exit verification system has been sought since after 9/11, but efforts to build one have been repeatedly stymied, most often because of the projected costs.