A new federal immigration rule aimed at keeping "mixed status" families together takes effect today.

The policy, which President Barack Obama initiated last year, allows certain undocumented immigrants who are immediate relatives of U.S. citizens to apply -- without having to leave the country -- for a waiver from a 10-year ban for unlawful presence in the country.

Previously, these immigrants had to leave the country and request a waiver at a specific U.S. consular office in the immigrant's country of origin. For Mexican immigrants, that meant traveling to the crime-ridden border city of Ciudad Juarez and waiting several months for the waiver process to run its course.

The new rule means Medardo Munoz doesn't have to leave his adopted son, Tobin, alone. Tobin, 24, has cerebral palsy, seizure disorders and a mild mental disability, so he requires around-the-clock care. Medardo Munoz is Tobin's primary caregiver, while his mother, Bonita Munoz, a U.S. citizen, works as an in-home support provider or is often away from home on union business.

"Without him being there, I wouldn't be able to make the living to support my family," said Bonita Munoz. "It's a relief that we can apply without having to go to Mexico for months and months."

The new rule affects immigrants who entered the United States illegally and for whom a green card is being requested by a relative who is a U.S. citizen, in many cases a spouse.

Immigration attorneys said the new rule could benefit hundreds, if not thousands, of undocumented immigrants on the North Coast. Nationally, the number could be as high as 1 million of the country's estimated 11 million undocumented immigrants.

The "provisional waiver" is granted in cases where the U.S. citizen spouse or close relative can prove separation from the undocumented relative would cause extreme hardship on the family.

Today marks the first day that families can apply for the waiver within the boundaries of the United States, and families have been waiting for this day since Obama proposed the new rule in January 2012. Once they are granted waivers, immigrants still must leave the country and go to U.S. consular offices in their native countries to obtain their visas.

But they do so with a waiver in their hand. In the past, many did not risk the chance of leaving the country and applying for a waiver for fear of being rejected and being separated from their families.

If they attempted to cross the border back to the United States and were caught, they triggered a lifetime ban from the country.

When immigration attorneys and certified immigration consultants learned of the proposed rule, they stopped filing waivers for their clients because of the risk of being denied.

"When we got wind that Obama was going to allow people to submit this waiver in this country, we said, 'Whoa, we don't want any appointments for our clients,' " said Kathy Differding, director of immigration and citizenship services for California Human Development Corp.

Differding said she has been sending provisional waiver cases to immigration attorney Stephen Scribner, who she said has been "flooded" with immigrants eager to submit their cases starting today.

"We have people in the hopper and he's been working on 25 to 35 waivers for my clients," she said.

Scribner, who is representing the Munoz family, said he's "never been this busy in 15 years. . . . It's borderline overwhelming for a solo practitioner."

The waiver policy was Obama's first major executive move last year to change immigration procedures without going through Congress. In August, Obama launched a program aimed at halting deportation of young people who, as children, were illegally brought into the country.

Bonita Munoz said her husband, whom she married six years ago, entered the country illegally more than 15 years ago. She said that in the past, he hasn't allowed her to file a petition for his green card for fear of being refused a waiver and being separated from them.

Now, she added, "We're going to the next stage."

You can reach Staff Writer Martin Espinoza at 521-5213 or martin.espinoza@pressdemocrat.com.