That means voters will have an unusually direct way of examining how they compare.
The Washington Examiner reviewed hundreds of votes from 2013 and 2014 to find cases where the three senators split on substantive issues.
Below are 10 votes where the three differed. To find out which one you would have voted most like, take this short quiz.
Overhauling immigration laws
The issue: A bipartisan group of senators proposed overhauling the nation's immigration laws, including creating a path to citizenship for millions of undocumented immigrants.
The vote: The bill passed the Senate 68-32 but has so far languished in the House. Cruz and Paul voted against, Rubio in favor.
The issue: After the ouster of Egyptian President Mohamed Morsi, Paul proposed redirecting $1.5 billion in foreign aid to the country to fix bridges in the United States.
The vote: The Senate rejected the amendment on an 86-13 vote. Cruz and Paul voted in favor, Rubio against.
Reforming an agricultural program for sugar growers
The vote: The amendment failed on a 45-54 vote. Cruz and Paul voted in favor, Rubio against.
Passing Rep. Paul Ryan's 2013 budget
The vote: The budget failed on a 40-59 vote. Cruz and Paul voted against, Rubio for.
Pairing increases in the debt limit with spending cuts
The issue: Sen. Rob Portman, R-Ohio, proposed an amendment that would require Congress pair any increase in the debt limit with the same amount in spending cuts.
The vote: The Senate voted 54-44 to table the amendment. Cruz and Rubio voted against tabling the amendment, Paul voted to table it.
The issue: Sen. Kirsten Gillibrand, D-N.Y., proposed removing the military chain of command from prosecuting sexual assault cases.
The vote: The Senate failed to reach the 60 votes needed to end debate on the bill on a 55-45 vote. Cruz and Paul voted to move forward with the bill, Rubio voted against it.
The vote: The Senate confirmed Kerry on a 94-3 vote. Paul and Rubio voted in favor, Cruz against.
The issue: President Obama nominated former Sen. Chuck Hagel, R-Neb., to serve as secretary of defense.
The vote: The Senate confirmed Hagel on a 58-41 vote. Cruz and Rubio voted against, Paul in favor.
The issue: President Obama nominated White House Chief of Staff Jack Lew to serve as secretary of the Treasury.
The vote: The Senate confirmed Lew on a 71-26 vote. Cruz and Rubio voted against, Paul in favor.
The vote: The Senate confirmed Brennan on a 63-34 vote. Cruz and Paul voted against, Rubio in favor.