On one side of the spectrum in the Senate there is Sen. Susan Collins of Maine, who has not missed a vote since taking office in 1997. At the opposite end are Ted Cruz of Texas and Marco Rubio of Florida.
The two Republican presidential candidates' attendance records when it comes to Senate votes and attending hearings are some of lowest in the chamber, with Cruz being especially negligent as a member of the Senate Armed Services Committee.
Cruz has missed the majority of committee hearings and now ranks 97th in the first three months of this year in showing up for roll call votes on the floor.
According to a report from Politico late last month, Cruz missed out on discussions about Afghanistan, the U.S. military prison at Guantánamo Bay, spending cuts, military readiness and the appropriate level of compensation for the troops.
Cruz was also the only senator absent on Wednesday when the Senate voted 99-0 to pass a compromise human trafficking bill that ended a contentious fight over federal abortion funding restrictions that had stalled the confirmation vote on attorney general nominee Loretta Lynch.
Cruz's campaign spokesman, Rick Tyler, told Fox News Latino that the senator missed the vote because he arrived in Washington, D.C., late in the evening on Wednesday.
The Texas senator is expected to be in Dallas Thursday for a fund-raiser hosted by investor Tom Hicks.
Cruz himself seems to embrace the fact that he is snubbing his colleagues and committee members, telling a crowd in Houston that he is "guilty as charged" when asked if he wouldn't get along with his fellow senators.
His absenteeism might be one reason why Sen. John McCain of Arizona, the current head of the Armed Services Committee, has attacked Cruz this week about comments that he is "pressing" the committee to have hearings on why the military has a policy of not allowing soldiers to carry their firearms onto bases.
"I hope the new chairman, John McCain, will agree to have those hearings because I think it's very important to have a public discussion about why we're denying our soldiers the ability to have their Second Amendment rights," Cruz said, according to a transcript provided to Fox News Latino by his office.
McCain fired back that he had not heard from Cruz on this and joked that the Texas lawmaker sent his message "through some medium that I'm not familiar with."
"There's a lot of holes in the ozone layer, so maybe it wasn't the ozone layer that he bounced it off of," McCain said, according to the Hill. "Maybe it was through hand telegraph, maybe sign language. Who knows?"
In regards to Cruz's attendance record, his staff said his attendance is not an accurate account of his participation in defense and foreign policy issues before the panel.
"Sen. Cruz is deeply engaged in defense and national security issues," said his communications director, Amanda Carpenter to Politico. "He never hesitates to defend American sovereignty and has established a remarkable track record leading on these matters."
She added that he has introduced legislation "to stop Americans who join ISIS from returning to the United States to wage jihad, impose sanctions on Iran to safeguard America and our ally Israel, and grant combat status for the troops who were sent overseas to fight Ebola."
In February, an analysis carried out by Vocativ in partnership with GovTrack.us, showed that Rubio beats Cruz as the senator most absent from chambers, having missed 99, or 8.3 percent, of 1,198 total votes since taking office in January 2011 to February of this year.
"He is one of the only senators with young children who has not moved his family to D.C., and tries to spend as much time in Florida with them as possible," Rubio spokesman Alex Conant told Politico. "In addition to his parental responsibilities, in recent years he's also had to return to Florida and miss votes due to his mother's health and civic responsibilities like jury duty."