President Bush is focused on winning over members of his own Republican Party in a bid to reform the U.S. immigration system.
There are two parts to the immigration debate. First, how to control the borders and stem the flow of illegal aliens into the United States. And second, how should the country deal with the 11 to 12 million illegal immigrants already inside the country.
In his speech this week, President Bush sought to find a middle ground.
"America can be a lawful society and a welcoming society at the same time," said Mr. Bush.
The president will dispatch thousands of National Guard troops to help shore up the southern U.S. border with Mexico.
That is important to many conservative Republicans in Congress who insist that border security is the top immigration challenge.
This is Senator Jeff Sessions, a Republican from Alabama:
"I think there are a lot of members of Congress that will not support legislation that they think is ineffective in enforcement at the border," said Mr. Sessions.
Sessions and other Republicans, especially those in border states, are getting an earful about illegal immigration from constituents like George Morin, who owns a cattle ranch in Arizona.
"Any of these big corporations that willingly hire them, I would love to see them just slapped? with a substantial fine, not a slap on the hand," he said.
President Bush also wants to establish a guest worker program and create a path to citizenship for the millions of illegal immigrants already in the United States.
But Republicans are split on comprehensive immigration reform. Late last year, House Republicans passed a bill that would build a fence along the Mexican border and would criminalize those illegal immigrants in the United States.
Some Republicans in the Senate, joined by opposition Democrats, favor a more comprehensive approach along the lines proposed by the president.
Senator Dick Durbin, a Democrat from Illinois, says it is up to Mr. Bush to unify his own party in support of comprehensive reform.
"The president has the power to call up the National Guard to patrol our border, but now he must summon the power to lead his own Republican forces in Congress to support a bipartisan, comprehensive immigration reform," said Mr. Durbin.
Experts say the political stakes in the immigration debate are high.
Georgetown University political analyst Stephen Wayne says President Bush and his fellow Republicans must be careful not to alienate Hispanic-American voters in their quest to enact immigration reform.
"One, the president has to try to gain Republican support, particularly in the House of Representatives," said Mr. Wayne. "And two, the Hispanics are the largest growing group in our society and in the electorate."
The action now is focused in the Senate, where debate on a comprehensive immigration reform bill is expected to lead to a vote by the end of May.
"The issue is whether there is anything else on the bill other than border security," added Stephen Wayne. "Some Republicans hope there is not. I think most Democrats and some Republicans hope that there is some kind of guest worker program."
Major differences between the Senate and House versions of immigration reform would have to be worked out through negotiations. But some experts believe that could be difficult because many lawmakers may not be willing to compromise on the issue as they prepare for re-election battles in the November congressional elections.