For a presidential cycle known for upending conventional political wisdom, one thing certainly hasn't changed: It's hard to vote in the Senate if you're campaigning across the country.
Like a young(er) John McCain from 2007, Sen. Marco Rubio, R-Fla., who missed every vote last week, leads the Senate in truancy for the year to date, voting just 68.7 percent of the time, according to CQ Vote Watch .
To his credit, he's still beating the 2007 version of McCain, the sitting senior senator from Arizona, who finished that year voting just 44.3 percent of the time on his way to becoming the 2008 Republican nominee.
Two other Republican senators hoping to be the 2016 nominee, Lindsey Graham of South Carolina and Ted Cruz of Texas, are voting only slightly more frequently than Rubio: 75.2 percent for Graham and 77.7 percent for Cruz — good enough for second and third place in votes missed Senate-wide for the year to date.
While the three Republicans are quick to point out their policy differences with President Barack Obama, 2016 Democratic hopeful Hillary Rodham Clinton and Vice President Joseph R. Biden Jr. — the maybe-he-will-run-maybe-he-won't candidate — the Republicans are pretty much in the same boat with Democrats when it comes to missing votes while on the trail.
In 2007, Obama, Clinton and Biden — all running for president while sitting senators, along with then-Sen. Christopher J. Dodd of Connecticut — were just as absent. Biden of Delaware voted 60.9 percent of the time, both Dodd and Obama of Illinois voted 62.4 percent of the time, and Clinton of New York voted 76.7 percent of the time.
Of course, two other presidential aspirants are showing that doing both is not impossible. Sen. Rand Paul, R-Ky., has voted 97.8 percent of the time this year to date, while Bernard Sanders, the Vermont independent who's running for the Democratic nomination, has voted 96.8 percent of the time.
Still, former Senate Majority Leader Bob Dole in 1995 set the standard: He voted 99 percent of the time while running for president. And even while securing the Republican nomination in 1996, the Kansas Republican voted 92 percent of the time.
Related: Bob Dole Reflects on Running for President as a Senator Balancing Act: A Day with Marco Rubio in the Senate Grassley's Iowa Advice for Presidential Hopefuls: Show Up See photos, follies, HOH Hits and Misses and more at Roll Call's new video site. Get breaking news alerts and more from Roll Call in your inbox or on your iPhone.