As a candidate, President Obama promised Latino voters that he would aggressively push for passage of a comprehensive immigration bill during his first year in office.

“What I can guarantee is that we will have in the first year an immigration bill that I strongly support and that I’m promoting,” Mr. Obama said in an interview with the Spanish-language broadcaster Univision in 2008.

Now, facing a re-election campaign next year, the White House is embarking on a public relations effort to reassure Latino supporters who say they are frustrated by the president’s failure to deliver on his immigration promise.

On Tuesday, Mr. Obama will travel to the United States border with Mexico to kick off a series of community conversations about the need for immigration reform. In a speech in El Paso, Mr. Obama will urge Congress to act, though officials said he would not unveil legislation nor demand a specific timeline.

“He’s trying to lead a constructive and civil debate on America’s broken immigration system,” a senior White House official said, speaking on background ahead of the president’s speech. “What the president is hoping to do is to drive momentum.”

Latino voters sided overwhelmingly for Mr. Obama in the 2008 election, with 67 percent picking the Democratic presidential ticket, according to exit polls. Rapid growth in the Hispanic population, especially in critical states in the Southwest, make the Latino population important for the president next year as he seeks another term.

In his speech, Mr. Obama plans to issue what officials said will be a “call to action” in which he urges Americans to pressure Republicans in Congress. The officials said the president will lay out his administration’s efforts to secure the border and will promote the economic benefits of a comprehensive immigration overhaul.

The president, officials said, wants to “create a sense of urgency around the country that matches his sense of urgency.”

But liberal and conservative Latino activists in Washington say the president will need to do more than that if he hopes to convince Latinos that he deserves their support in 2012.

“If they think that this is going to be the thing that mobilizes an increasingly disappointed Latino electorate, I think they’re wrong,” Frank Sharry, executive director of America’s Voice Education Fund, a pro-immigration reform group, said in an interview Monday.

Mr. Sharry said the likelihood of a grand immigration bargain with Congressional Republicans is all but dead. But he said Mr. Obama needed to offer his Latino supporters bold executive action — such as limiting the numbers of people being deported — to prove that he is trying to accomplish something.

“They are going to have to have to make some big administrative action to make up for the fact that he promised big,” Mr. Sharry said.

Alfonso Aguilar, executive director of the Latino Partnership for Conservative Principles, called Mr. Obama’s speech “purely political” and said Latino voters would not be moved by words alone.

Mr. Aguilar, who served as the chief of the office of citizenship in George W. Bush‘s administration, said Mr. Obama needed to propose specific legislation and begin discussions with House Speaker John A. Boehner and the Republican leadership in the Senate.

“He’s talking to everyone except those people who really count,” Mr. Aguilar said. “At the end, you can do all the events that you want, but if Latinos don’t see any serious action on immigration it won’t matter. We need to see a White House plan.”

Mr. Obama has said repeatedly that he needs to see some indication from Republicans that they are willing to seriously consider a comprehensive approach to immigration before the issue can move forward. In a speech in July 2010, Mr. Obama blamed the other party for keeping the issue in gridlock.

“I’m ready to move forward. The majority of Democrats are ready to move forward, and I believe the majority of Americans are ready to move forward,” Mr. Obama said at American University. “But the fact is, without bipartisan support, as we had just a few years ago, we cannot solve this problem.”

But Republican leaders who once supported such efforts, including Senator John McCain of Arizona, have signaled they have little interest in working with Mr. Obama. After pushing the issue during his primary campaign in 2007, Mr. McCain has dropped his support for comprehensive immigration reform, stressing the need for increased border security first.

In the short term, a stalemate could be challenging for Mr. Obama as he tries to explain to his once-committed supporters why he was able to make progress on health care and other issues, but not on immigration.

But White House officials have said they believe the long-term issue favors Democrats as the growth in the Latino population coincides with the increasingly aggressive tone from Republican politicians. Last year’s debate over an Arizona immigration law highlighted Republican rhetoric that angered many Latinos.

Mr. Aguilar conceded that Latino disappointment with Mr. Obama could be offset by anger at the harsh rhetoric coming from some Republicans.

“What we are telling Republicans is that if you follow the strategy of four years ago, you are not going to win enough Latino voters to win the White House,” Mr. Aguilar said. “Republicans have an opportunity. But it all depends at the end if the president acts and what the reaction of Republicans is.”

“If they pull a McCain,” Mr. Aguilar said, “then they are not going anywhere.”

White House officials said Mr. Obama would offer a “blueprint” on Tuesday for making progress toward an immigration overhaul and said it would look similar to the statements he has made over the past year.

“The president is leaning in and asking others to lean in with him,” one official said.