Within hours of voters’ giving Republicans legislative control in Washington and dealing President Barack Obama a sharp rebuke in the process, Latino groups clamoring for immigration reform began telling both parties that inaction before the 2016 elections will come at a price.

“For us, the election of 2016 starts today,” said Ben Monterroso, executive director of Mi Familia Vota. “The vote taken yesterday sends a very clear message. We want action on issues that matter to our community … The Republican Party now has the responsibility to govern.”

Latinos are an increasingly powerful presence in elections. By the 2016 presidential election, 28 million Latinos will be eligible to vote, up from 25 million now. Even more eligible Latino voters are on the horizon. More than 900,000 Latinos will turn 18 every year from now until 2028 — more than 12 million over 14 years — and Latinos who turn 18 in the United States are more likely to be eligible to vote because most were born here.

And they want Obama to act. He delayed executive action on immigration reform this year until after the midterms so any backlash would not hurt Democratic candidates.

Deferring deportation of undocumented immigrants is high on Obama’s list of immigration reform options. Also under consideration is extending protection to parents of those who arrived in the U.S. as children and to undocumented parents of U.S. citizens. Together, these options could cover up to 4 million immigrants, and Democrats know what that might mean: In 2012, when Obama launched the Deferred Action for Childhood Arrivals program by executive order, Latino support for Democrats soared.

While immigration reform advocates would prefer legislative action that would extend protection to more immigrants here illegally, they doubt it will happen, especially now that Republicans — who have generally opposed anything resembling amnesty — are in control.

“I don’t believe for a minute that Republicans are going to do anything,” said Frank Sharry, executive director of America’s Voice, an immigration reform group.

Executive action may be the only way to achieve immigration policy change for now, he said, but “the administration should be well aware that if it goes small (on immigration reform), it’s going to get as much grief from Republicans, but if it goes big, it will get more love from Democrats and Latino voters.”

To prove his point, Sharry said Latino voter turnout was low in most states but that candidates who supported immigration reform were rewarded. He pointed to the re-election of New Hampshire’s Democratic Sen. Jeanne Shaheen as evidence that candidates who included immigration in their campaign agendas received Latino backing.

Colorado Democratic Sen. Mark Udall, who did not make immigration an issue in his campaign, lost to Republican Cory Gardner.

Latino Decisions, a leading Latino opinion research firm, conducted an election eve poll in 10 states and a national sample. It surveyed Latinos who voted in recent elections and newly registered Latino voters, asking them specifically about the Colorado Senate race.

“We asked voters in our sample, ‘Do you know exactly where Udall and Gardner stand on immigration?’” said Matt Barreto, a co-founder of Latino Decisions. Forty percent didn’t know Gardner’s position, and 47 percent were not sure of Udall’s stance.

While Obama received 87 percent of the Latino vote in Colorado in 2010, support for Democratic candidates dropped to 70 percent this year — in part, the poll suggested, because immigration reform was not a prominent issue in the key race.

“How about the Democrats who seemed to be awfully cautious when it comes to immigration reform?” Sharry asked. “That didn’t work out for them.”

The Latino Decisions poll found that the Latinos who voted Tuesday were less likely to support Democrats than in the previous three elections and that their frustration with both parties kept turnout low. It also found that about 68 percent of Latinos who could vote but did not said they would feel more enthusiastic about Democratic candidates if Obama takes executive action on immigration reform before the end of the year.

“We think that these nonvoters can become voters in 2016,” Barreto said.

But that may not mean they will automatically vote Democratic. Latinos’ traditional support has softened, said Gary Segura, another founder of Latino Decisions, which was commissioned by major Hispanic organizations to conduct the poll.

“Forty-eight percent report that Democrats truly care about the Latino community,” he said. “That’s the lowest number in a couple of years.” Only a third of Latinos polled this week said they think Democrats really care, and 22 percent think Democrats are outright hostile to Latinos.

Most Latinos said they voted to support the Latino community on issues that matter to them — such as immigration, jobs and the economy, education and health care.

The poll found that only 4 in 10 Latino voters were contacted by get-out-the-vote groups — a third of them from community organizations.

“But whites overwhelmingly received contact from their political party,” Barreto said.

“Outreach and mobilization efforts were anemic,” said Janet Murguía, president and CEO of the National Council of La Raza, the largest national Hispanic civil rights and advocacy group. “We need to do more to reach out.” Her organization registered 120,000 Latino voters this year.

“The midterms have come and gone, and the clock has started ticking on the 2016 race,” she said. “I would say to the president, ‘Act boldly to bring relief to families facing deportation’ … We’re headed into an election where our community will have the power to decide who will be the next president of the United States.”