Senate Republicans will delay a vote on their Obamacare replacement bill until after July 4 as they face opposition from enough GOP members to block the measure, according to NBC News and other reports.

Senate Majority Leader Mitch McConnell, R-Ky., had pushed to approve the bill this week, before senators leave for a holiday recess. He was set to speak to reporters on Tuesday.

As of Tuesday afternoon, five Republican senators — enough to block a procedural motion to proceed with the bill — said they would oppose the motion barring changes to the plan. A Congressional Budget Office score on Monday said that the proposal would lead to 22 million more uninsured Americans by 2026, only complicating matters for moderate GOP senators on the fence.

President Donald Trump invited all senators to a White House meeting at 4 p.m. ET on Tuesday, according to NBC News and Politico.

Republicans face difficulties in winning over skeptical senators, as tweaks to appease conservatives could alienate moderates, or vice versa. The hurdles threaten to delay a key plank of the sweeping agenda Republicans hoped to pass when Trump won the White House and the GOP held onto both chambers of Congress.

GOP Sen. Susan Collins of Maine, a swing vote, said Monday night she would vote “no” on the motion to proceed, tweeting that the Senate bill does not “fix the flaws” of Obamacare. She joined Sen. Dean Heller, a vulnerable Nevada Republican who previously said he would vote against advancing the bill as written due to its rollback of Medicaid expansion.

On the conservative side, Sens. Rand Paul of Kentucky and Ron Johnson of Wisconsin also said they would not back a motion to proceed this week for the bill as written. Sen. Mike Lee of Utah also said he would oppose the procedural move barring tweaks to the bill, according to the AP. They argue that the plan does not go far enough to repeal Obamacare.

After meeting with Trump at the White House earlier Tuesday, Paul said in a tweet that the president is “open to making the bill better.” He questioned whether “Senate leadership” was open to making what he calls improvements.

The GOP could still win skeptical senators over with amendments. House Republicans did the same to gather more votes before the chamber narrowly passed its own Obamacare replacement last month.

The House GOP initially had to pull its health-care bill from the floor in March when it became apparent that it would not get enough votes.

House Speaker Paul Ryan said Tuesday that he has “every expectation” the Senate will pass a health-care bill, adding, “I would not bet against Mitch McConnell.”

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