President Obama tried Friday to address concerns among Democrats and immigration advocates about how and when he will take promised executive action to overhaul the nation’s immigration policies.

The debate over how Obama should address immigration has caused a fissure among the president’s allies and congressional Democrats in recent weeks. The Democrats are divided over whether the president should take executive action before the elections or hold off until after so he can assess the political makeup of Congress heading into his final years in office.

Obama allowed on Friday that he would make a decision “fairly soon,” but his comments did little to reassure those who had been pushing him to act before the November elections, on the theory that bold executive action could spur turnout among Democratic voters and earn the party broader support from business and agricultural groups.

Increasingly, those voices appear on the losing end of a struggle within the party.

“We get it,” said Frank Sharry, founder and executive director of America’s Voice, an immigration reform group. But Sharry, a generally supportive ally of the White House on immigration matters, seemed especially frustrated Friday. Obama “has a track record of making promises in the immigration arena and failure to deliver. This has the feeling of yet another promise made that might not be kept,” he said.

“It’s such a squandered opportunity to make history,” he added.

Even as Obama reviews his options, several of his top advisers, including Valerie Jarrett and domestic policy chief Cecilia Muñoz, began reaching out this week to labor leaders and immigration activists to say that he is likely to wait until after the elections to announce changes.

Several Democratic senators locked in tight reelection battles have suggested in recent days that Obama should wait for Congress to act. In a campaign debate this week, Sen. Kay Hagan (D-N.C.) said Obama “should not take” executive action to ease deportations. And Sen. Mark Pryor (D-Ark.) said in a statement that the White House is “sending mixed messages” on immigration. He faulted partisanship for stalling progress on immigration but added: “That doesn’t give the President carte blanche authority to sidestep Congress when he doesn’t get his way.”

White House aides are explaining the delay by saying that the substance of Obama’s executive actions will be more important than the timing, according to several people who received calls.

Janet Murguía, president of the National Council of La Raza, said, “Normally the substance does matter over the timing. But for our community, this is converging. This is now about the president’s legacy.”

Many House Democrats agree and believe that executive actions would bolster turnout in key elections this fall and would only produce criticism from those who already oppose the president.

“What people want is leadership, and this idea that I’m going to wait for political reasons — it’s one thing if you do that and nobody knows what you’re going to do. It’s another thing when you signal you’re going to do something but then wait until after the election,” said Rep. Joe Garcia (D-Fla.), who has met several times this year with Obama and administration officials to discuss immigration.

Rep. Luis V. Gutierrez (D-Ill.), a longtime immigration reform advocate, was more direct. In a sharply worded op-ed published by the Guardian’s American news Web site Thursday, he called on “timid colleagues to get out of the way and let the president take action.”

“The Democrats cannot say that we stand with immigrants if that secretly means we only stand with immigrants in odd-numbered years or when southern Democrats complain,” Gutierrez wrote.

Senate Democratic strategists, however, believe that the long-term policy and political goals are better served by delaying the decision until after November. Incumbents such as Pryor, Hagan and Sens. Mary Landrieu (D-La.) and Mark Begich (D-Alaska) are locked in extremely close races, and their victories would almost assure a Democratic majority in the Senate. However, if the Democrats lose the Senate after an executive order is issued, congressional Democrats could blame that decision for their losses and then imperil the immigration activist movement for years to come.

Sen. Michael F. Bennet (D- Colo.), chairman of the Democratic Senatorial Campaign Committee, has relayed some concerns from senators to the White House, according to advisers. He supports taking action but believes that the border crisis with unaccompanied Central American minors must be dealt with first. He has encouraged White House officials to take broader executive actions that would win support from business groups, labor unions and agriculture interests — key members of the coalition that supported the sweeping immigration legislation that passed the Senate in 2013.

Some senior party strategists also reject the idea that an executive order would spur liberal turnout this fall. Those advisers suggest that base voters increase turnout on issues such as these when there are actual initiative or referendum on the ballots, when voters see a direct correlation between their vote and a law taking effect. In this case, Obama’s decision will have already been made, the strategists said.

Before departing the NATO conference in Wales on Friday, Obama was asked during a news conference when he might take action on immigration.

“My intentions is that in the absence of action by Congress, I’m going to do what I can do within the legal constraints of my office, because it’s the right thing to do for the country,” Obama said.

If Congress doesn’t act, Obama said he will seek to bolster border security and lay out plans for illegal immigrants to obtain legal status so that they will “be able to not look over their shoulder but be legal since they’ve been living here for quite some time.”

That is the first time Obama has suggested he might be seeking to grant at least temporary legal standing to millions of undocumented immigrants. Such protection likely would be granted to the parents of hundreds of thousands of children — generally referred to as “dreamers” — who were granted temporary legal standing in 2012. The possibility of extending the legal protections to adults has been suggested by advocates and administration officials for several months.

David Nakamura contributed to this report.

David Nakamura contributed to this report.