Q&A: US immigration debate

Illegal immigration is a deeply divisive issue in the United States, and a hot political topic ahead of the November mid-term elections. As Congress wrestles with reform of current laws, the BBC News website answers some key questions.

How big is the problem?

There are thought to be about 11.5 million illegal immigrants in the United States, and each year some 500,000 to a million more enter the country, mostly through the 2000-mile (3,200-km) southern border with Mexico.

Many of these people are poorly educated, unskilled workers, yet in their thousands they fill the sort of jobs that most native-born Americans will not take, at least not for the same price.

Much of California's agriculture relies on migrant labour, for example. But some argue these jobs would be filled, even without illegal immigrants.

What most agree on is that at present, the US system is failing all its stakeholders: foreigners who want to enter the country, citizens who expect it to prevent illegal border crossings and employers who look to it for workers to fill jobs.

Why is the debate so charged?

Polls suggest that a majority of Americans see illegal immigration as a very serious problem for the US, and it is likely to be one of the key issues on which the public will judge politicians running for office in the November mid-term elections.

Strength of feeling on the issue was illustrated in March 2006 when hundreds of thousands of activists marched in California to protest against plans to criminalise undocumented workers.

It has also been reflected in the rise of Minutemen groups - citizens who have taken it upon themselves to police the US borders, and to confront illegal workers in cities around the US.

The issue is also politically awkward for Mr Bush's Republican party, because it brings into conflict two of its core constituencies - social conservatives and the business lobby.

Several key players in the immigration debate are likely candidates for the White House in 2008.

What are the key issues?

The political debate over immigration reform is crystallised around several key issues.

These include the enforcement of the country's land borders and existing laws on immigration, changes in the law to deal with people already in the country illegally, and how to offer a regulated route into the US for what the business community says are much-needed workers.

Some advocate greatly expanding physical barriers, like fencing, that already exist along some 100 miles of the border near cities - and bringing in tougher penalties for businesses caught employing illegal migrants.

Plans for various guest worker programmes, and provisions allowing the millions of illegal immigrants already in the US to remain legally, are also being hotly debated.

What stage is Congress at?

Last year, the House of Representatives passed a bill stuffed with tough new criminal measures and enforcement proposals, triggering the recent wave of demonstrations ahead of the Senate debate on the issue.

The Senate's judiciary committee has been working frantically to come up with proposals that strike a balance between enforcement and putting current undocumented workers on the path to citizenship.

But senators from across the political spectrum have put forward a number of competing proposals.

Senate Majority Leader Bill Frist has introduced an enforcement-only bill. Senators John McCain, a leading Republican, and Ted Kennedy, a liberal Democrat, have plans that give illegal immigrants an eventual path to US citizenship.

Republican Senators John Cornyn and Jon Kyl - from the border states of Texas and Arizona - want a guest-worker programme, but would make foreign workers eventually go home and re-apply there to return.

Whatever legislation emerges from the Senate will have to be reconciled with the House bill before it can be signed into law by the president.