I’ll believe when it happens.

Senate Majority Leader Harry Reid is increasingly focused on the month of July as the time to exercise the so-called “nuclear option” and revisit filibuster reform, and he has privately told top advisers that he’s all but certain to take action if the Senate GOP blocks three upcoming key nominations, a senior Senate Democratic aide familiar with his thinking tells me.

Reid has privately consulted with President Obama on the need to revisit filibuster reform, and the President has told the Majority Leader that he will support the exercising of the nuclear option if Reid opts for it, the aide says, adding that senior Democrats expect the President to publicly push for it as well. “If Senator Reid decides to do something on nominations, the president has said he’ll be there to support him,” the aide says.

Reid is eyeing a change to the rules that would do away with the 60-vote threshold on all judicial and executive branch nominations, the aide says, on the theory that this is a good way to immediately break an important logjam in Washington — without changing the rules when it comes to legislation.

“This would take away the right to filibuster on nominations,” the aide says. “All executive branch and judicial nominations would be subject to majority votes. He would not do it on legislative items.”