Three female senators excluded from all-male healthcare policy talks appear to have just derailed an attempt by the Republican leadership to put forward a measure that would repeal parts of Obamacare without an immediate replacement.

Republican Senators Susan Collins of Maine, Shelley Moore Capito of West Virginia and Lisa Murkowski of Alaska immediately declared that they could not vote for such a plan.

With a majority of 52 senators, Senate Majority Leader Mitch McConnell could only afford to lose two 'yea' votes on his latest plan to dismantle Obamacare, which he announced on Monday after efforts to repeal and replace the healthcare law at the same time – one of Donald Trump's key campaign promises – collapsed.

Mr McConnell had assembled a 13-senator working group to craft the now-defunct healthcare bill, which was released last month. Observers have called the defections by Ms Collins, Ms Capito and Ms Murkowski the “revenge of the GOP women” for not being included in the healthcare talks.

Barely two days into writing the bill, the Majority Leader and other legislators were bombarded with questions about why no women had been included on the panel.

“The working group that counts is all 52 of us,” Mr McConnell told reporters in May. “Nobody is being excluded based upon gender ... Everybody's at the table. Everybody.”

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But Democrats accused their colleagues on the other side of the aisle of crafting “a secret healthcare plan” behind closed doors, “which I really hope is not happening in the men's locker room,” said Senator Patty Murray, a member of Democratic leadership.