WATCH: Raffi Williams explains why the Senate refuses to take a recess.
You can almost hear the crickets here on Capitol Hill, and that's because it's August -- which means that most lawmakers are back in their districts for summer recess.
But when is a recess not a recess?
The simple answer is when the Senate decides not to call it a recess, but that doesn't tell the full story.
Where things get interesting
Senate Republicans are blocking more than 100 of President Obama's judicial and regulatory nominees. According to the Constitution, unless the Senate gavels in once every three days, the president can appoint his nominees -- like Supreme Court nominee Merrick Garland -- without Congressional approval.Here's where things get interesting: The Senate calendar calls for the chamber to be in recess until September 6, but the Republicans in Senate don't want the president's nominees to take office without their approval.
Merrick Garland accepting the nomination to the Supreme Court in the Rose Garden.
Gavel in, gavel out
So instead of taking an official recess, the Senate holds "pro forma" sessions, when a lone senator gavels in and gavels out, without taking up any legislative action. Sometimes these sessions last less than a minute. By holding pro forma sessions and not taking an official recess, the president is unable to appoint his nominees. Senators are able to go back to their districts to meet with constituents or just take a vacation.
Sen. John Barrasso (R-WY) presiding over a pro forma session earlier this year.
Both parties play by the rules
Republicans are not the only ones to use pro forma sessions. When George W. Bush was president, the Democrats used the same approach.
Most often, the senators who oversee the sessions are those from states nearest to the capital, like Virginia, Delaware, or Maryland.
The House of Representatives, on the other hand, can take an official recess, because they don't confirm nominees.
Supreme Court rules on the tactic
The Senate's refusal to take an official recess has frustrated the president. In 2012, Obama tried to make recess appointments despite the Senate being in a pro-forma session.
In 2014 the Supreme Court ruled that these appointments were illegal and the Congressional stalling tactic was constitutional.