Republicans, meanwhile, have been growing increasingly restless, with the House Oversight Committee probing Trump's security protocols for discussing classified information at his weekend retreat in Mar-a-Lago, and Senate majority leader Mitch McConnell suggesting that the Senate investigation of Russian interference in the election would expand.
I'm not sure what this means. However, I tried to construct a section of the sentence I especially have difficulty understanding it. This is my interpretation.
The original phrase: the House Oversight Committee probing Trump's security protocols for discussing classified information
My attempt to paraphrase: the House Oversight Committee investigating Trump's security system to discuss secret information
Source: TIME February 27/ March 6, 2017: White House Chaos Theory