Pragmatic conservatives were holding out Monday as President Trump and House Republican leaders whipped votes for the amended Obamacare repeal bill.

The focus has been on centrists, who as a faction constitute the lion's share of the current opposition to the package to repeal and replace Obamacare. They're prone to oppose the party on occasion given the competitiveness of their districts. That's especially the case on healthcare reform.

The breadth of the Republicans' political problems on the American Health Care Act could run deeper.

There is a small but rising number of Republicans who are team players and can be reliably counted on to take tough floor votes who are signaling to the White House and House GOP leaders their dissatisfaction with the latest version of the bill.

Several hail from districts Hillary Clinton won in November, or that were competitive. That puts extra pressure on their vote and offers Trump little in the way of leverage to move them, as they look ahead to 2018.

"There is no solid GOP governing majority yet," said Republican strategist Rob Stutzman, who is based in California, where a handful of Republicans represent Clinton districts. "Trump won but his inability to lead on an agenda has created a huge leadership vacuum which leaves many Republicans in Congress simply fending for themselves."

The first version of the Republican bill to partially repeal and replace the Affordable Care Act, former President Barack Obama's healthcare law, died in late March when conservatives from safe red districts balked. They said "no" despite their voters' support for Trump and his attempts to sway them.

Now, Republican centrists and conservatives in suddenly more competitive districts are holding out, concerned about changes to the bill that critics charge would reduce insurance guarantees, such as prohibiting the denial of coverage based on pre-existing medical conditions (supporters say the alterations will reduce premiums and increase access to care.)

The various whip counts reveal the hurdle Republican leaders and the White House have to jump to get the healthcare bill to the Senate.

House Foreign Affairs Committee Chairman Ed Royce is a new addition to the ranks of the official undecideds. The California Republican holds an Orange County-based district that voted for Clinton over Trump by a 51.5 percent to 43 percent margin.

Royce is a top House GOP fundraiser who as a party chairman is considered a part of the leadership team. He's a pragmatic conservative and almost always delivers for leadership when they need him.

The same attributes apply to Rep. Fred Upton, R-Mich., the former chairman of the House Energy and Commerce Committee. Upton's district swung for Trump over Clinton, 51.3 percent to 43 percent. That would suggest Upton shouldn't be worried.

But a GOP insider with Michigan ties said Upton has keen political radar.

Although his concerns about the policy of the AHCA shouldn't be discounted, this insider said, Upton's district is not as safe as the results of the 2016 presidential election make it appear. If the congressman is worried about the politics, he could have reason to.

"Fred is always worried about re-election and how the national winds will blow," the GOP insider said, on condition of anonymity in order to speak candidly. "His district isn't all that great and one we always worry about when he leaves."

Rep. Mario Diaz-Balart, R-Fla., is another red flag for House GOP leaders and the president.

Diaz Balart is a leadership ally who complained bitterly in late March when leadership had to pull the health care bill because of conservative opposition. The House Freedom Caucus, he said at the time, needed to learn how to compromise.

Now Diaz-Balart is unsure of his vote, concerned that the changes, negotiated by key conservative and centrist leaders, that he frets would undo popular coverage guarantees that his constituents depend on.

Voting for the AHCA in its present form could be a problem for him in 2018 in a district that only voted narrowly for Trump over Clinton, 49.6 percent to 47.9 percent.