(CNN) President Donald Trump railed against Senate rules requiring 60 votes to overcome a filibuster in a series of tweets Saturday morning, just a day after the chamber dealt a devastating setback to the GOP effort to repeal and replace Obamacare.

"Republicans in the Senate will NEVER win if they don't go to a 51 vote majority NOW," Trump tweeted. "They look like fools and are just wasting time."

Sens. John McCain , Lisa Murkowski and Susan Collins joined with Democrats to oppose a "skinny repeal" of Obamacare early Friday morning, a major blow to Trump and the Republicans' congressional agenda.

Trump fumed at the loss after the vote, tweeting that the three Republicans "let the American people down," linking them to the Democrats who were uniformly against the plan.

Current Senate rules mandate that 60 senators -- three-fifths of the 100-member Senate -- must agree in order to end debate and move forward to a vote on a measure or piece of legislation -- a process known as invoking cloture.

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