WASHINGTON, DC, USA (AP) — There are varying and strong opinions about how best to refer to the 11 million-plus people who are in the US without legal permission.

Illegal immigrants?

Undocumented workers?

Unauthorised population?

Illegal aliens?

The last has generally fallen out of favour. Some immigrant advocates are pressing a “Drop the I-Word” campaign, arguing that it is dehumanising to refer to people as “illegal”.

“Undocumented worker” often isn’t accurate because many aren’t workers, and some have documents from other countries. Homeland Security reports refer to “unauthorised immigrants”, but the agency also reports statistics on “aliens apprehended”.

Definitions, please:

* Legal permanent residents (LPRs): people who have permission to live in the US permanently but aren’t citizens. They’re also known as “green card” holders. Most of them can apply for citizenship within five years of getting green cards. In 2011, 1.06 million people got the cards.

* Refugees and asylees: people who come to the US to avoid persecution in their home countries. What’s the difference between the two terms? Refugees are people who apply for protective status before they get to the US. Asylees are people who apply upon arrival in the US or later.

* Naturalisation: The process by which immigrants become US citizens.

Going green

Is there an actual green card? Indeed there is.

It’s the Permanent Resident Card issued to people who are authorised to live and work in the US on a permanent basis. In 2010, the Government redesigned them to add new security features — and make them green again.

The cards had been a variety of colours over the years. New green cards are good for 10 years for lawful permanent residents and two years for conditional residents.

Path to citizenship

There’s a lot of talk about creating a “path to citizenship” for immigrants who are in the US without legal status.

But there’s vigorous debate over what conditions these immigrants should have to satisfy to get citizenship — among them are paying taxes, fines and fees, and passing background checks.

Some legislators want to set additional conditions, such as improvements in border security and in tracking whether legal immigrants leave the country when required. Others want to limit immigrants who are in the US illegally to some sort of legal status that stops short of citizenship.

But more than 60 per cent of Americans think those who are here illegally should have a way to become citizens, according to an Associated Press-GfK poll conducted in April.

The Senate bill would allow those in the country illegally to obtain “registered provisional immigrant” status six months after the bill was enacted, if they met certain conditions.

Additional border security improvements would have to go into place before anyone obtained green cards or citizenship.

It would take immigrants living here illegally at least 13 years to get all the way to citizenship. They’d have to pay taxes, fees and US$2,000 in fines. No one who entered the country after December 31, 2011, or had a felony conviction or more than three misdemeanours would be eligible.

The A-word

Nothing stirs up a hornet’s nest like talk of amnesty for immigrants who are in the country illegally, although there’s a lot of disagreement over how to define the term.

A 2007 effort to overhaul the immigration system, led by Bush, failed in part because Republicans were dismayed that it included a process to give otherwise law-abiding immigrants who were in the country illegally a chance to become citizens. Critics complained that would be offering amnesty.

All sides know it’s not practical to talk about sending 11 million-plus people back to their countries of origin. So one big challenge this time is finding an acceptable way to resolve the status of those who are in the country illegally.

Backers of the Senate bill stress that those who are in the country illegally would have a longer and more difficult path to citizenship under their plan than would immigrants who followed all the rules.

Getting a reprieve

While the larger immigration debate goes on, the Government already is offering as many as 1.76 million immigrants who are in the country illegally a way to avoid deportation, at least for now.

Obama announced a programme in June that puts off deportation for many people brought here as children. Applicants for the reprieve must have arrived before they turned 16, be younger than 31 now, be high school graduates or in school, or have served in the military. They can’t have a serious criminal record or pose a threat to public safety or national security.

Applications for the Deferred Action for Childhood Arrivals programme are averaging more than 3,000 a day. By mid-April, nearly 489,000 people had applied and more than 268,000 had been approved, with most of the rest still under consideration.

Applications have come from all 50 states, with the largest number coming from California and Texas. Nearly 75 per cent of the applicants are originally from Mexico.

In some ways, the programme closely tracks the failed DREAM Act, which would have given many young illegal immigrants a path to legal status. Obama’s programme doesn’t give them legal status but it at least protects them from deportation for two years.

History: Doing the wave

The US is in its fourth and largest immigration wave.

First came the Colonial era, then an 1820-1870 influx of newcomers, mostly from Northern and Western Europe. Most were Germans and Irish, but the gold rush and jobs on the transcontinental railroad also attracted Chinese immigrants.

In the 1870s, immigration declined due to economic problems and restrictive legislation.

The third wave, between 1881 and 1920, brought more than 23 million people to the US, mostly from Southern and Eastern Europe, aided by cheaper trans-Atlantic travel and lured by employers seeking workers.

Then came the Great Depression and more restrictive immigration laws, and immigration went into decline for decades.

The fourth wave, still underway, began in 1965 with the end of immigration limits based on nationality. Foreign-born people made up 1 in 20 residents of the US in 1960; today, the figure is about 1 in 8.

History: Here a law, there a law

Until the late 1800s, immigration was largely a free for all. Then came country-by-country limits. Since then, big changes in US immigration law have helped produce big shifts in migration patterns.

Among the more notable laws:

* 1965 Immigration and Nationality Act: Abolished country-by-country limits, established a new system that determined immigration preference based on family relationships and needed skills, and expanded the categories of family members who could enter without numerical limits.

* 1986 Immigration Reform and Control Act: Legalised about 2.7 million immigrants living in the US illegally, 84 per cent of them from Mexico and Central America.

* 1990 Immigration Act: Increased worldwide immigration limit to a “flexible cap” of 675,000 a year. The number can go higher in some years if there are unused visas available from the previous year.

* 1996 Immigrant Reform and Immigrant Responsibility Act. Expanded possible reasons for deporting people or ruling them ineligible to enter the US, expedited removal procedures, gave state and local police power to enforce immigration laws.

* Post-2001: In 2001, talk percolated about a new immigration plan to deal with unauthorised immigrants, guest workers and violence along the Mexican border. But the September 11 terrorist attacks of 2001 put an end to that, amid growing unease over illegal immigration.

About last time…

The last big immigration legalisation plan, in 1986, took six years to get done.

The law, signed by President Ronald Reagan, had three main components: making it illegal to hire unauthorised workers, improving border enforcement and providing for the legalisation of a big chunk of the estimated three million to five million immigrants then in the country illegally.

The results were disappointing on two central fronts: The hiring crackdown largely failed because there was no good way to verify eligibility to work, and it took a decade to improve border security. As a result, illegal immigration continued to grow, fuelled by the strong US economy.

What did work as intended: Close to three million immigrants living in the US without permission received legal status. By 2009, about 40 per cent of them had been naturalised, according to Homeland Security.

Latinos rising

Census figures show that between 1960 and 2010, immigration from Europe declined while the numbers coming from Latin America and Asia took off. As the immigrants’ points of origin changed, so did their destinations. Concentrations shifted from the Northeast and Midwest to the South and West.

A few Census Bureau snapshots:

* In 1960, there were fewer than one million people in the US who were born in Latin America. By 2010, there were 21.2 million.

* In 1960, 75 per cent of foreigners in the US came from Europe. By 2010, 80 per cent came from Latin America and Asia.

* In 1960: 47 per cent of the foreign-born lived in the Northeast and 10 per cent in the South. By 2010, 22 per cent lived in the Northeast and 32 per cent in the South.

The fence

The fence between the US and Mexico runs off and on for 651 miles along the 1,954-mile border. Most of it has been built since 2005. At some points, it’s an 18-foot-high steel mesh structure topped with razor wire. At others, it’s a rusting, 8-foot-high thing, made of Army surplus landing mats from the Vietnam War.

The fencing is one of the more visible manifestations of a massive effort over the past two decades to improve border security. The results of that effort are dramatic. Those images of crowds of immigrants sprinting across the border illegally while agents scramble to nab a few are largely a thing of the past.

Two decades ago, fewer than 4,000 Border Patrol agents worked along the Southwest border. Today there are 18,500.

Plummeting apprehension statistics are one measure of change: 357,000 last year, compared with 1.6 million in 2000. The numbers are down in part because fewer are trying to make it across.

The border isn’t sealed, but it is certainly more secure.

The Senate bill would require the Government to have even tougher border security plans before those who are in the country illegally could become legal permanent residents.

Who’s hanging around

With tighter border security and years of economic difficulty in the US, it turns out that most of the immigrants who are in the US without permission have been there for a while. Just 14 per cent have arrived since the start of 2005, according to Homeland Security estimates. In contrast, 29 per cent came during the previous five years.

At the peak in 2000, about 770,000 immigrants arrived annually from Mexico, most of them entering the country illegally. By 2010, the pace had dropped to about 140,000, most of them arriving as legal immigrants, according to Pew.

Who’s leaving?

Mexicans, mostly. Since 1986, more than four million non-citizens have been deported. Deportations have expanded in the Obama Administration, reaching 410,000 in 2012 from 30,000 in 1990. Most of those deported — 75 per cent — are sent back to Mexico. Nearly half of those removed had prior criminal convictions. So far, the Obama Administration has deported more than 1.6 million people.

To naturalise or not

Lots of US immigrants who are eligible to become naturalised citizens don’t bother. As of 2010, about two-thirds of eligible immigrants had applied for citizenship, according to the Migration Policy Institute. That lags behind the rate in other English-speaking countries such as Australia and Canada, which do more to promote naturalisation.

Why bother?

What’s so great about citizenship?

Naturalisation offers all sorts of rights and benefits, including the right to vote and run for office. Naturalised citizens are protected from losing their residency rights and being deported if they get in legal trouble. They can bring family members into the US more quickly.

Certain Government jobs and licensed professions require citizenship. Citizenship also symbolises full membership in US society.

In 2010, there was a 67 per cent earnings gap between naturalised citizens and non-citizen immigrants, according to a report from the Migration Policy Institute. Even after stripping out differences in education, language skills and work experience, naturalised citizens earned at least five per cent more.

Skipping it

Nearly two-thirds of the 5.4 million legal immigrants from Mexico who are eligible to become US citizens haven’t done so, according to a Pew study released in February. Their rate of naturalisation is half that of legal immigrants from all other countries combined. The barriers to naturalisation cited by Mexican non-applicants include the need to learn English, the difficulty of the citizenship exam and the US$680 application fee.