House Republicans, bedeviled by mistrust, infighting and influential outside forces, are struggling to advance an Obamacare repeal package and prove that their majority can deliver results.

The American Health Care Act, on the surface, is bogged down over a debate about whether the bill provides adequate coverage guarantees for Americans with pre-existing medical conditions.

But veteran House Republicans said in interviews Tuesday that their problems run deeper. They lack the unity, mindset and political will to make the hard choices required to govern.

The healthcare breakdown is just another symptom of this broader political virus that seems immune to all antibodies, including President Trump, the Republican who took up residence in the White House in January.

"The failure here has not been in our leadership, it's certainly not been in the president, it's been in our inability to overcome our own differences and our lack of trust in one another," Rep. Tom Cole, R-Okla. said.

House Republicans won 247 seats in 2017, providing a 29-seat cushion above the 218 votes they need to pass legislation. It's a historic House majority for the GOP, yet not enough (apparently) to get big things like healthcare done.

Even the omnibus spending bill, negotiated by President Trump to fund the remainder of fiscal 2017, was on track to pass the House without 218 Republican votes thanks to bipartisan support from the Democrats.

In all, it's a familiar outcome for House Republicans.

During their six years in power under President Barack Obama, they periodically failed to advance conservative legislation because they couldn't reach internal consensus. Must-pass spending legislation typically relied on Democratic votes to clear.

Republicans just didn't expect the dysfunction to continue after Trump took office, and with House Speaker Paul Ryan, R-Wis., calming the restlessness that had built up after nearly a decade of John Boehner at the top as minority leader and speaker.

"There may come a reckoning between the president and some members of the Republican House to where there needs to be a showdown and he needs to take a stand," Rep. Tom Rooney, R-Fla., said.

Indeed, governing was supposed to get easier with the prospect of seeing priorities such as the repeal and replacement of Obamacare signed into law by Trump, and with outside pressure to oppose Obama becoming irrelevant.

Some Republican insiders fault missteps by Ryan and the president. But in interviews with about a dozen current and former House Republicans, and current and former House GOP aides, most of the blame was heaped on members.

Too many arrived in Washington during the Obama era, and remain trapped in an opposition mindset bent on obstruction. Old school Republicans say it's a marked difference from the get-things-done approach that predominated under GOP majorities that governed from 1995-2007.

"It starts with the will to compromise and reach consensus," said Tom Reynolds, a New York Republican who served in the House from 1999-2009 and was part of leadership. "We've just kind of gotten away from that."

During Reynolds' tenure in the majority, House GOP leaders could wield earmarks — federal money for district projects — to cajole resistant members. Leadership could also use fundraising as a cudgel. The party tightly controlled access campaign cash and wayward members risked being cut off come re-election time.

That has changed.

House Republicans passed parliamentary rules banning earmarks, when they won back the majority in 2010. Social media and the Internet allow members to raise money and drum up grassroots support without party support.

Changes in election law led to a proliferation of outside groups, flush with cash with sport more political influence over members more concerned about losing a GOP primary than they are to upsetting leadership.

Critics of the party establishment, and they are legion, have celebrated the liberation of members from leadership's influence. But it's led to frayed relationships and a lack of cohesion that at times cripples House Republicans to get things done.

This systemic intraparty division is what's driving the GOP's logjam on healthcare, held up first by faction of conservatives and now by a faction of centrists. And tax reform could be the next victim, if House Republicans don't get their act together.

"We have got to start governing, and legislating the Trump agenda," a frustrated Rep. Ann Wagner, R-Mo., said.