At age 43, U.S. Sen. Cory Gardner of Colorado is the youngest lawmaker in a generation to lead the national fundraising machine dedicated to expanding Republican ranks in the Senate.

Not so long ago, it was the kind of job an ambitious politician could use as a steppingstone to something more — and, in Gardner’s case, it still could.

But things are looking rough right now.

The National Republican Senatorial Committee has seen a recent plunge in fundraising, driven by what many donors see as the party’s stymied agenda in Congress.

Potentially more troublesome is the civil war between party leaders and Republicans aligned with former White House adviser Steve Bannon. This rift has already drawn the committee into an Alabama primary election in which it first backed the unsuccessful establishment candidate and later the far-right insurgent — and eventual nominee — Roy Moore.

The shift in support risks attacks from both a vocal faction of Republicans as well as Democrats eager to tie the NRSC to candidates such as Moore, who once wrote that U.S. Rep. Keith Ellison, a Minnesota Democrat and Muslim, shouldn’t be allowed to serve in Congress because of his religion.

Taken together, Gardner should expect to walk a tightrope for the rest of his two-year term, said one political observer who described some Republicans as “in open revolt.”

“There isn’t a lot of love lost with the political establishment, particularly on the Republican side,” said Nathan Gonzales, editor and publisher of the nonpartisan political analyst group Inside Elections, “and that’s something the chairman is going to have to continue to navigate.”

Stymied fundraising

The most outward sign of trouble for the NRSC is its recent fundraising.

After a fast start to the year, the group has seen a sharp drop in contributions. In September, the NRSC raised just $2.2 million, compared with $4.5 million collected by the rival Democratic Senatorial Campaign Committee.

That comparison is not an outlier either. The DSCC has dwarfed the NRSC the past three months: $11.5 million to $6.3 million.

The low totals are especially pronounced given that in March the NRSC broke its own monthly record for a nonelection year by snagging a whopping $7 million in contributions.

The early edge is why the NRSC isn’t panicking — yet — as it says overall fundraising for 2017 is ahead of past nonelection years.

But the recent drop hasn’t gone unnoticed.

As reported by The New York Times, Gardner told his Republican colleagues in September that the lack of a major legislative win, such as a repeal of the Affordable Care Act, had infuriated the Republican donor base.

He indicated as much in a recent interview.

“I think people are anxious for Congress to get its work done,” Gardner said. “People expect the majority to accomplish the things they said they would. That means you pass legislation on tax reform that grows the economy (and) you continue to work on escalating health care costs.”

Republicans in Colorado and Washington both said the GOP has a lot riding on its latest push — a bid to overhaul the tax code — and that the effort could make or break its ability to maintain its slim, 52-seat majority in the 100-member Senate.

“There is no question there’s frustration among some of our supporters with the health care vote,” said Republican U.S. Sen. Thom Tillis of North Carolina, who serves as vice chair of the NRSC. “I mean, the primary reason to do tax reform is because of the economic gain that we’ll get. The other compelling reason is we have to prove that we’re a governing majority and we can produce a result.”

The constant pressure from party donors isn’t unique to the GOP or Gardner. Democratic U.S. Sen. Michael Bennet of Colorado, who led the DSCC for the 2014 election cycle, recalled a similar vibe.

“A huge part of that job is fundraising and a huge part of that job is being on the phone,” he said. “In all of these instances, people are very interested in giving you their opinion on the direction of the party. Virtually every call is someone telling you what they think.”

Democrats lost control of the Senate the year Bennet chaired the DSCC — with one of those losses coming in his home state of Colorado with Gardner’s defeat of then-U.S. Sen. Mark Udall.

But Bennet was spared much of the blame and won his own re-election in 2016.

“In my experience, (party) chairmen don’t often get held responsible for the outcome of elections,” said Jennifer Duffy of the nonpartisan Cook Political Report.

She said she didn’t see that for Bennet and that it probably would be the same for Gardner.

Gardner also benefits from a Senate map that favors the GOP — in that many more Democrats are up for re-election in 2018. That means the NRSC has fewer states to defend and more opportunities to go on offense.

Ultimately, Gardner’s new NRSC-generated relationships with Republican donors and colleagues could help his career in the long term. Former Senate Majority Leader Bill Frist and current Majority Leader Mitch McConnell both once served as NRSC chairs.

Working around the unrest

But Gardner is battling more than just Democrats this cycle.

He also has to contend with opposition from within his own party — the face of which is Bannon, a former adviser to President Donald Trump and provocateur with the right-wing Breitbart News Network.

Bannon got behind Moore in Alabama — beating the NRSC and Republican incumbent Luther Strange in the process — and he has threatened to support primary challenges against senators he deems as part of the establishment.

As the NRSC is bound to protect its incumbents, similar intraparty clashes are likely in states such as Mississippi and Nevada, where Bannon-aligned Republicans are looking to unseat U.S. Sen. Roger Wicker — a former NRSC chair — and U.S. Sen. Dean Heller, respectively.

This type of family fight isn’t new, said Dick Wadhams, former chair of the Colorado Republican Party. But past years “didn’t have the intensity of what we are seeing in 2017,” he said.

So far, Gardner has avoided much of the criticism Bannon and his allies have directed at more senior leaders such as McConnell.

And Gardner has the backing of GOP lawmakers who have clashed with Trump, notably outgoing U.S. Sen. Jeff Flake of Arizona. “This is a tough time and there are divisions in the party and to have someone like Cory who’s optimistic, who gets along with everybody (and) and who presents a good face — that’s as good for the party as we can get,” Flake said.

Gardner’s armistice with his fellow Republicans, however, has elicited criticism from Democrats back in Colorado — notably as it relates to Moore.

The former judge strongly opposes gay rights and marriage, has questioned the U.S. citizenship of former President Barack Obama and has made the baseless claim that there are Midwest communities living under Muslim Sharia law.

After Moore’s primary win, Gardner said in a statement that the NRSC would support him and that Moore was “imperative to passing a conservative agenda.”

To that end, the NRSC recently was one of several groups to open a joint fundraising account with Moore’s campaign — although it’s uncertain how much the NRSC ultimately will have to spend to try to keep Alabama in Republican hands.

The moves stand in contrast to Flake and U.S. Sen. Ben Sasse, R-Neb., who have criticized Moore, notably over his remarks on Islam.

Morgan Carroll, who chairs the Colorado Democratic Party, said Gardner now bears culpability for Moore. “It is fictitious to pretend that Cory Gardner as a person is different than what’s coming out of the NRSC,” Carroll said.

The Denver Post asked Gardner what he thought of some of Moore’s views and asked him to identify any he took exception to.

Gardner would not name examples but said he would “make it clear where I agree and disagree with anyone — and I have done that over the past many years — and I will continue to do that going forward.”