US: President Bush will make the case for comprehensive immigration reform in a live, televised address from the Oval Office tonight, the first such broadcast he has made on an issue other than war.
"He is going to talk about his principles for immigration reform. This is a critical issue for the American people," a White House spokeswoman said.
The speech comes as the Senate starts debating a Bill that would allow most of America's estimated 12 million illegal immigrants, who include tens of thousands of Irish citizens, to remain legally in the US.
Mr Bush is expected to back the legalisation of most immigrants but also to propose that the National Guard gets involved in the federal government's efforts to stop illegal immigration at the US-Mexico border. National Guard units, which are under the command of state governors during peacetime, have played a major role in the war in Iraq and some governors have criticised the border proposal.
"The federal government should put up the money to create the kind of protection the federal government is responsible to provide. I think what we should do is press the federal government that that's their responsibility, not the state's responsibility," said California governor Arnold Schwarzenegger.
Senate Majority Leader Bill Frist yesterday defended the proposal as the only short-term solution to stem the flow of illegal immigrants across the border from Mexico.
"The only thing that we can do to secure our borders right now is to give our states help, and that is best done through the National Guard," he said.
Republicans and Democrats in the Senate last week resolved a procedural dispute that derailed an immigration reform Bill last month and both parties are now optimistic that the Senate will pass legislation by the end of next week.
Any Bill the Senate passes must be merged with a tough, anti-immigration Bill approved by the House of Representatives last year, which would criminalise illegal immigrants and impose tougher penalties on those who employ them.
Senator Edward Kennedy, one of the prime movers behind immigration reform in the Senate, said Mr Bush could play an important role in persuading conservative Republicans to support a comprehensive Bill.
"We need the president to become involved. We need his leadership more than anything else," Mr Kennedy said.
It remains unclear how effective Mr Bush's persuasion will be, given that his approval rating has hovered above 30 per cent for weeks and fell to 29 per cent in one poll on Friday.
In only four states out of 50 does Mr Bush enjoy an approval rating above 50 per cent, and Republicans facing re-election in November may be reluctant to take a political risk in supporting him.
Conservative Republicans are determined that a final immigration Bill should not include a "path to citizenship" for illegal immigrants, a proposal they describe as amnesty.
Under the Bill being debated in the Senate, most illegal immigrants could eventually apply for US citizenship if they pay a fine, stay in work and pay all back taxes.