Immigration: For and against Obama's election-year move
The US is to end deportation of illegal migrants who arrived in the US as children, and will offer work permits to those who meet eligibility criteria.
The move is expected to offer some 800,000 people the chance to live and work legally in the US, and comes months ahead of a tight presidential election in which Hispanic voters are seen as crucial in several swing states.
So is the new policy an enlightened move or a cynical - and possibly unconstitutional - political ploy? We asked several migrants and policy experts for their views.
Erika Andiola, 24, undocumented immigrant from Mexico
I was brought here by my mom - she was escaping domestic violence from Mexico. Half of my family is US citizens. It was the best choice that she could have made and I'm very thankful for her.
When I was a child from 11 until I grew up, I was really fearful to go back to Mexico because of my dad. It wasn't a situation where he would give me a spanking - it was real violence.
Now, as an adult I could make different choices, but I've grown up in this country, I've considered myself right now to be an American and I'm willing to fight for this country and to give back to this nation. If I go back to Mexico, I haven't been there for so long I don't consider it to be my home anymore.
I've been living in Arizona for close to 14 years, and I actually graduated from Arizona State University in 2009. I have my degree, I have what it takes to use my degree, but I haven't been able to.
This is a great first step. I am very thankful for the president to come out and to do this - it took a lot of courage and I'm really thankful for it.
We're able to be here without having the fear of walking out the door and getting stopped by the police and getting sent to immigration. We can be here without those worries.
But we're definitely going to be pushing more next year to make sure that we get the Dream Act and comprehensive immigration reform, but it's a great first step.
Mark Krikorian, Center for Immigration Studies
I don't think it's too much to describe this as a lawless act. This really is making immigration law without input from Congress. Any congressman who applauds this is undermining his own constitutional function. The president is attempting to rule by decree and there is absolutely no excuse for this.
I have a 16 year-old. If he and I snuck into Mexico to live, he'd be psychologically an American the rest of his life.
Moving the initial age of entry down to, say, seven, which is what the common law and the Church regard as the age of reason... I could potentially live with.
That's what the democratic process is supposed to be about: you have differences and you work them out. The president is saying he couldn't care less what the constitution says about the process of making law.
Gaby Pacheco, 27, undocumented immigrant from Ecuador
I came to the US when I was a young girl. Since I got here I always felt America was my home and I did everything possible to show people how much I loved my home.
If you go to get your eyes checked - everything's blurry then you put on glasses and everything clears up. That's what it was like. It was clean and palm trees and safe.
After six years of having to do car washes and fundraisers and breaking every family and friends' piggy bank, I was able to graduate [from university]. I have three degrees in early childhood education, music education and special education.
It's a first step, but we need something longer-lasting. We're going to need legislation that could make sure that I have a path to citizenship and that I'm able to be a full American. I have a sister that won't benefit because she's 32.
Roy Beck, president of NumbersUSA
Today, in an unconstitutional move, President Obama thwarted the will of Congress and shunned the 20 million under- and unemployed Americans by announcing he will grant work permits to two to three million illegal workers.
Congress on three occasions rejected Dream Act amnesties in part to help unemployed workers born here or who came here legally.
Simon Rosenberg, president of think tank NDN
The Democrats have wanted to fix the broken immigration system. The vehicles to do that were legislative, and have been blocked by the Republicans.
There's been tremendous frustration. This was responding to something that was seen in our family as particularly egregious: these undocumented kids who had no decision on coming on their own, many of whom are high-performing students at a time when the country needs entrepreneurs.
Clearly they figured out a way to do this from an administrative standpoint without having to go through Congress and they decided to do it.
The practical outcome of this is that it will help the president with Latino voters, and it will help the president with all voters because it will make him look like he's trying to solve problems and not play politics.
If the GOP gets characterised as blocking reasonable, common-sense solutions, that's going to hurt them with Latinos and the overall public.