Eight years ago, the last time sitting senators launched competing quests for a presidential nomination, each touted their congressional records as evidence they were more the true agent of change than the other one.  

In the end, of course, Democratic voters decided Barack Obama was the preferred choice for disrupting the capital’s status quo. But the empirical evidence available during their campaign revealed only the slightest difference between Obama’s and Hillary Rodham Clinton’s voting habits. During their previous three years together in the Senate, both toed the party line more than 96 percent of the time while opposing President George W. Bush’s wishes on about 3 out of every 5 votes.  

That reminiscence is appropriate now, for two connected reasons. At least three Republican senators are hoping their Senate records help set themselves apart in the 2016 presidential field. And CQ Roll Call has a new online tool available for assessing the similarities and differences among them.

(Related: Obama Gets His Way in GOP-Controlled Senate, Vote Study Shows)

This week, our newsroom colleagues are launching CQ Vote Watch to provide up-to-date presidential support, party unity and attendance record numbers for every member — and the current averages for their colleagues in each House or Senate partisan caucus.  

Beyond that, custom searches will permit studies of voting behavior by various ideological factions, ethnic groups, state delegations or any other subset in the news. For those eager to track voting patterns before this year, data since the beginning of the previous decade is there for the massaging. All the numbers used to be published only annually; now they’ll be available in close to real time.  

On Friday, after the Senate finished its 12th  legislative week of this year, a test drive of CQ Vote Watch provided ready insight into how Ted Cruz of Texas, Rand Paul of Kentucky and Marco Rubio of Florida are starting to use their jobs to distinguish themselves.  

Cruz, the most overtly combative of the trio, has not only opposed Obama more often than his announced rivals but also more frequently than any other Republican in the Senate. On votes when the president’s wishes have been clearly articulated in advance, he’s gone the other way 82 percent of the time — on all but three of the 17 relevant roll calls since January. That’s almost evenly split between nomination confirmations and legislative matters.  

Rubio is close behind , having bucked the president on 76 percent of those votes. (Last week, for example, he and Cruz were among only eight senators, all Republicans, who voted against clearing the legislation revamping the way Medicare pays physicians , which Obama had heartily endorsed.) Paul, in contrast, has a 2015 presidential opposition score of 47 percent, statistically on the mark of the 46 percent Senate GOP average.  

The running tally also makes clear that, with Republicans having taken control and promising more freewheeling debate, GOP senators are getting more opportunities to express their differences with the president. Last year, when Democratic leaders worked to shield their vulnerable incumbents from politically difficult votes, all but 20 of the 145 presidential position votes were on mostly non-controversial nominations, and as a result Cruz, Paul and Rubio all voted as Obama wanted more than half the time.  

This year is so far shaping up to be similar to last year, however, when it comes to party unity — how frequently the politicians stick with their team during votes that position most members of one party against most members from the other.  

The year-to-date average Senate Republican party unity score is 94 percent, and there’s not much daylight between that and the partisanship evidenced by the presidential trio. Rubio (98 percent) and Cruz (97 percent) are small notches above that benchmark. But Paul (92 percent) is only slightly below, despite marketing himself as more libertarian and different from the typical GOP senator on matters including personal privacy and national security.  

One way Paul has been setting himself apart is in his performance of one of the most basic congressional responsibilities: answering the call of the roll.  

Like the others, he was laying the groundwork for his presidential run when the year began. But unlike them, he almost never let those efforts get measurably in the way of his day job. Of the 154 recorded votes this year, Paul has missed only two so far, or just 1 percent. That’s slightly better than the current 2 percent absenteeism average for all senators.  

But his rivals have been absent more this year than any other Republicans. Rubio has skipped 21 percent of the votes and Cruz has missed 18 percent. (Rubio missed 10 percent of votes last year, more than any other senator who was not retiring or running for re-election.)  

Lindsey Graham of South Carolina, who’s been traveling extensively to help decide if he’ll also seek the GOP presidential nomination, has been the third-most-frequently absent GOP senator — 12 percent of the time this year. He’s opposed Obama on 47 percent of votes, right at his conference’s average, while reaffirming his reputation as an unpredictable conservative with a below-average 84 percent party unity score. Only five GOP senators have gone against the grain more often.  

It’s a good bet all the senatorial White House aspirants will be gone even more often the rest of the year — and generally missing in action at the Capitol next year, too, for as long as their campaigns keep going. (Obama did not participate in 53 percent of the votes in the two years before resigning his Illinois seat. GOP Sen. John McCain of Arizona skipped 64 percent during that same 110th Congress. After losing the nomination, Clinton came back to her New York Senate seat for six months before becoming secretary of State, so her absenteeism rate in those years was a comparably modest 25 percent.)  

Will Cruz, Rubio, Paul or maybe Graham be AWOL the most? Who among them will go on record most often against the man they’d like to succeed? Who will be the most loyal party stalwart along the way? For the users of CQ Vote Watch, regularly updated answers are just a few keystrokes away.  

CQ subscribers will find Vote Watch at CQ.com. Get more information on subscribing here. 
Related:

Check out CQ Vote Watch


Vote Studies Show Double-Sided Numbers for Senate’s ‘Red State Four’


Lessons for This Year in Voting Patterns of Last Year


Jeb Bush Can’t Be Nominated. Or Can He?


It’s Early: Why Pundits Shouldn’t Overreact


Ted Cruz Biography: the CQ Profile


Rand Paul Biography: the CQ Profile


Marco Rubio: The CQ Biography


2016: An Unanchored, Puzzling Presidential Election


The Young and the Restless of 2016


The 114th: CQ Roll Call’s Guide to the New Congress


Get breaking news alerts and more from Roll Call in your inbox or on your iPhone.