In an effort to placate conservatives, Mr. Bush talked tough about cracking down on immigrants who slip across the United States' long border with Mexico.

But the real theme of his speech was that the nation can be, as he phrased it, "a lawful society and a welcoming society at the same time" and that Congress could find a middle ground between deporting illegal immigrants and granting them immediate citizenship.

What was remarkable to people who knew Mr. Bush in Texas was how much he still believes in the power of immigration to invigorate the nation.

"He's always had a more welcoming attitude," said Bruce Buchanan, a presidential scholar at the University of Texas. "He always spoke well of Mexican nationals and regarded them as hard-working people. So his grace notes on this subject are high."

Mr. Bush had three political goals in making the speech: appealing to the public's desire to see something done, mollifying an important part of his Republican base and shaping a compromise between competing immigration bills in the Senate and House. Republicans acknowledge that it will be difficult for Mr. Bush to reach these goals with Democrats arrayed against him and with his own party so split on the issue.

It is also unclear if Congress can even enact an immigration bill this year when the Senate is pushing a temporary guest worker program and the House favors a harsher, enforcement-only approach. So far Mr. Bush, who insists he is not advocating amnesty, has spoken favorably of the Senate approach — a position consistent with his views in the past.

"He understands this community in the way you do when you live in a border state," said Israel Hernandez, an assistant secretary at the Commerce Department who traveled with Mr. Bush as a personal aide when he first ran for governor. "Philosophically, he understands why people want to come to the U.S. And he doesn't consider them a threat."

There were no major battles over immigration or immigration legislation when Mr. Bush was governor, but he is remembered for saying emphatically that the children of illegal immigrants had a right to go to Texas schools. His views were in sharp contrast to those of another politician of the time, Pete Wilson, who closely tied his successful 1994 race for California governor to Proposition 187, a ballot initiative that denied public services to illegal immigrants and that passed overwhelmingly.

"There was never any effort to cut off benefits, and Bush basically bought into the notion that they were going to be Texans," said Paul Burka, senior executive editor of Texas Monthly, who closely followed Mr. Bush then. "He didn't believe in closing the borders."

Mr. Bush first met Mexican immigrants at public school in Midland, Tex., where Hispanics made up 25 percent of the population. Later, when he owned a small, unsuccessful oil company, he employed Mexican immigrants in the fields. When he was the managing partner of the Texas Rangers, he reveled in going into the dugout and joking with the players, many of them Hispanic, in fractured Spanglish.

"In every dimension of his career, whether it was politics or the private sector or the sports world, he's been engaged with the Hispanic population," Mr. Hernandez said.

Mr. Bush was also living in a state that has stronger historical and cultural ties to Mexico than any other.

"The cultures mingled much more freely here than in California," Mr. Burka said. "Here there was not nearly as much antipathy. There were always workers coming over, and they were very essential."

At the same time, Karl Rove, Mr. Bush's veteran political adviser, recognized that there was potential in the Hispanic vote and that Republicans could appeal to them on abortion, religion and family values.

"Karl has always been a strong believer that Hispanics were a natural Republican constituency," Mr. Burka said. "He once told me that 'we have about 15 years to put this together.' "When Mr. Bush got to the White House, immigration was going to be a signature issue, a key to his relationship with President Vicente Fox of Mexico and essential in attracting Hispanic voters to a Republican Party that Mr. Rove envisioned as dominant for decades to come.

The Sept. 11 attacks suspended the push on the issue until late in the first term, but in a speech in January 2004 Mr. Bush threw himself into the subject with personal passion.

"As a Texan, I have known many immigrant families, mainly from Mexico, and I have seen what they add to our country," Mr. Bush told hundreds of wildly cheering Hispanics at a gathering in the East Room of the White House. "They bring to America the values of faith in God, love of family, hard work and self-reliance, the values that made us a great nation to begin with."

Every generation of immigrants, he added, "has reaffirmed the wisdom of remaining open to the talents and dreams of the world."

Mr. Bush's speech that day, more than 2,300 words, devoted only 200 of them to border security. Even then, he mentioned only what he said the nation was doing right — employing more Border Patrol agents and improving technology — and made no urgent statement, as he did Monday night, that "we do not yet have full control of the border."

In that same speech, Mr. Bush proposed a temporary guest worker program for the nation's 11 million or so illegal immigrants, as well as for immigrants seeking to enter the United States. The reaction was immediate and largely negative; immigrants and many Democrats said the plan did not go far enough, and conservatives said it amounted to amnesty.

Mr. Bush dropped the proposal as too risky for his 2004 re-election race, but he campaigned heavily among Hispanic constituencies and attracted 40 percent of the Hispanic vote.

With the election out of the way, Mr. Bush picked up the issue last October, but by then he had changed his emphasis to border security to calm conservatives. On Monday night, with his polls showing a drop in conservative support in part because of his immigration proposals, he toughened his language even more.

Now immigration, as divisive as it is, remains as Mr. Bush's last major domestic issue and a test of his remaining powers as president.

"He's putting capital behind it," said Mark McKinnon, the president's campaign media consultant. "It would be a lot easier just to let it go away."