By Billy House, Bloomberg News (TNS)

WASHINGTON — As top U.S. lawmakers haggled over a must-pass spending bill, House Democratic leader Nancy Pelosi last week slipped in one more request to Speaker Paul Ryan: reviving federal research on gun violence.

The gun proposal, like Democratic demands for tax breaks for the middle class and poor, is a way to set themselves apart from House Republicans. It also links their longshot bid to win the majority in 2016 with Democratic front-runner Hillary Clinton’s push for firearm controls in her presidential campaign.

“We will always have a big focus on gun-violence prevention,” Pelosi of California reiterated to reporters on Friday in Washington after pitching the research effort in a conversation with Ryan earlier in the day.

The comeback challenge is daunting: Democrats would have to gain 30 seats in November to take the House, now controlled by Republicans. And so far, Democrats’ efforts at forging their 2016 legislative message have been less substantial and more diffuse than those of Republicans — leaving them to rely on Clinton to give the party’s congressional candidates a lift.

Ryan is using the spending talks to show Republicans can govern. He already gave a speech on Dec. 3 spelling out a detailed “pro-growth” agenda, an early road map of what his members will run on in 2016.

Ryan is avoiding much talk about his party’s potential presidential nominee and any Republican nervousness over inflammatory rhetoric from front-runner Donald Trump. House Republicans will focus on laying out a positive vision for the country, he told reporters Thursday.

“I don’t think that we have the time to wait until a nominee arrives, which could be as late as, I don’t know, June or July,” said Ryan of Wisconsin, his party’s 2012 vice presidential nominee. “What I learned in presidential campaigns is you have to start talking about these issues early.”

With Republicans grabbing most of the public attention with a hotly contested primary race and a new House speaker who’s already a political star, Democrats are forced to try to break through with policy proposals such as the gun-research one reacting to this month’s massacre in San Bernardino, Calif. Congress has banned gun violence research by the Centers for Disease Control and Prevention for 19 years.

Democrats also are seeking to continue wind and solar tax breaks, as well as a permanent extension of the current Child Tax Credit, the Earned Income Tax Credit and the college-tuition tax credit.

Their campaign-year talking points won’t be rolled out until closer to the election, perhaps as late as August, said Rep. Steve Israel of New York, who is in charge of message development.

For now, House Democrats are talking more about how they’ll get a big boost from the top of the presidential ticket, with a kicker also that voters are tired of long-running House Republican dysfunction.

“It depends on what happens on the presidential, too, I keep reminding people,” said Pelosi during an interview on PBS’s Charlie Rose program with Al Hunt of Bloomberg News.

Non-presidential election years — such as 2014, when Democrats lost 13 House seats and plummeted to the smallest House minority since the 1920s — “are like the lounge act. So, who goes there, right?” Pelosi said in November.

Pelosi is careful not to declare Clinton as the obvious winner of her party’s 2016 nomination — not directly, that is.

“We have three great candidates. Any one of them would walk into that Oval Office with all the values of our country; we would be very proud of them whoever she may be,” she said on PBS.

Democrats say that if Clinton carries the 2016 presidential banner, that would boost fundraising and turnout for women, minorities and other Democrats.

“Democrats are prepared to seize on opportunities in the political atmosphere, whether they are presented by the ultra-conservative House of Representatives or the circus of Republican presidential candidates,” Democratic Congressional Campaign Committee Chairman Ben Ray Lujan of New Mexico said in a statement to Bloomberg.

With these hopes, Lujan and Democratic Party strategists in Washington say they are digging deep into the electoral map and finding an expansive battleground that could stretch to as many as 65 seats viewed as competitive to some degree.

Democratic leaders aren’t predicting a “wave” election in 2016 that would turn over the House majority. Democrats say Republicans are likely to struggle to hold seats in swing districts in states including New Hampshire, Maine, New York and Illinois.

The nonpartisan Rothenberg & Gonzales Political Report lists 31 U.S. House seats “in play,” 25 of which are held by Republicans. Thirteen of those are depicted as pure tossups, with three held by Democrats and 10 by Republicans.

Gaining 30 House seats in one election isn’t impossible. In 2006, Pelosi oversaw Democrats’ net gain of 31 seats that gave them the majority and made her the first female House speaker. Democrats held onto that majority for four years.

©2015 Bloomberg News. Distributed by Tribune Content Agency, LLC.

Photo: U.S. House of Representatives Democratic Leader Nancy Pelosi (D-CA) sits down for an interview with Reuters on House legislative plans, in her office at the U.S. Capitol, in Washington, December 2, 2015. REUTERS/Mike Theiler