Series: The Breakdown How politics and government really work, and why they don’t.

On a Monday afternoon in October 2011, West Virginia Democrat Nick J. Rahall II waited at the Charleston airport for a 4:50 p.m. U.S. Airways Express flight to Washington. If the plane left on schedule, the roughly 80-minute flight would allow him to get to the Capitol in time for votes in the House of Representatives that evening.

Things did not go according to plan. The flight didn’t leave Charleston for another four hours, giving Rahall, then the top Democrat on the House Transportation & Infrastructure Committee, plenty of time to “boil over,” as he later wrote. When he finally arrived in Washington, having missed three votes, he lambasted the airline’s handling of the delay in a statement in the Congressional Record:

“At moments, the arrival/departure information was so confused that the airplane would have had to violate the laws of physics in order to abide by the airline schedule,” Rahall’s statement read. “Needless to say, all passengers were inconvenienced and the airline’s explanations were wholly unsatisfactory. This flight delay prevented me from carrying out my Constitutional duty to represent the people of southern West Virginia: I feel I owe them and this body an explanation about why that was not possible last night.”

Voting is one of the most important duties of a lawmaker, and most miss very few votes. Yet voting attendance has become a topic of discussion in the Republican presidential primary, as Florida Sen. Marco Rubio has missed about a third of all votes this year, by far the most in that chamber.

In the House, unlike the Senate, lawmakers are given a chance to provide “Personal Explanations” to explain missed votes. These entries filed in the Congressional Record say not only how a Representative came to be absent, but also how they would have voted though they don’t have the effect of adding or changing a vote.

The custom has been in place since at least 1845, according to a 2008 Congressional Research Service report.

In a telephone interview, Rahall said he wanted it on the record that he would have voted in support of the three bills the House considered that day — a measure to convey federal land in Utah to the state, another changing the rules for granting ski area permits on national forest land and a third granting submerged land surrounding the Northern Mariana Islands to the American territory — if only to prevent political opponents from using the missed votes against him.

“They could end up as a 30-second sound bite in a campaign,” he said. (Rahall was defeated in 2014 by Evan Jenkins, a Republican).

ProPublica has collected all of the Personal Explanations filed since 2007 — some 5,058 in all, covering 21,176 votes — and created a database that lets readers look up their representatives’ missed votes, as well as their explanations. These statements are by no means required — only one in six absences are explained — but they document a little-discussed aspect of the lives and work of lawmakers, and provide hints at the competing priorities and difficulties of a system that, to many, seems chronically dysfunctional.

The reasons lawmakers cite most for missing votes range from the mundane (travel delays, often due to weather, or remaining in their districts for job fairs) to more personal (the birth of a child or a graduation ceremony or illness). Lawmakers have missed more than 2,000 votes for medical reasons, and thousands more for personal and family reasons.

The record is full of stories documenting the working lives of Representatives: Marcy Kaptur, a Democratic congresswoman from Ohio, missed a 2008 House vote because she was searching the Capitol for high school students visiting from her district. Jeff Landry, a Louisiana Republican, “completely lost track of time” and missed two votes in 2011. For Ben Ray Lujan, Democrat of New Mexico, an “operational issue” with a House voting machine meant that a 2012 vote wasn’t recorded.

For some, avoiding a vote is a sign of defiance. In 2012, Jan Schakowsky of Illinois was one of 108 Democrats who declined even to vote on a resolution holding then-Attorney General Eric Holder in contempt of Congress. She was the only one, though, to insert a statement in the Record saying she would have voted no: “I would not participate in what I strongly believe was an abuse of power by the majority.”

Although many explanations are short, lawmakers can be more expansive when a key issue is at stake. When J. Randy Forbes, a Virginia Republican who has missed less than 3 percent of votes since 2007, was absent for a January 2015 vote on a bill to ban federal funding for abortion, his explanation provided no reason, but emphasized his stance on the issue: “I am and always have been pro-life, and throughout my tenure in Congress will continue to be a strong advocate for the unborn.”

The Rules of the House say that “Every Member shall be present within the Hall of the House during its sittings, unless excused or necessarily prevented, and shall vote on each question put, unless having a direct personal or pecuniary interest in the event of such question.” Lawmakers routinely saythatthey take their voting responsibilities seriously, and in general attendance records bear that out: most lawmakers participate in the overwhelming majority of votes held.

How Do Congressional Representatives Vote, Anyway? Voting is one of the most important duties of a lawmaker, and they do it a thousand times a year or more. How does the House’s voting system work? Read the story.

Democrats have missed more votes than Republicans since the beginning of 2007, but they account for an even greater share of the explained missed votes: two of every three since the beginning of 2013.

Luis Gutierrez, an Illinois Democrat, has missed nearly one in six votes this year, according to voting records, one of the highest rates among current members of the House. He has been absent for 15 percent of all votes since the beginning of 2007, often due to his work on immigration policy, which frequently has him on the road.

“Congressman Gutierrez prioritizes constituent case work and spending time in the District in Chicago,” said Douglas G. Rivlin, a spokesman for Gutierrez, in a statement emailed to ProPublica. “He also devotes a great deal of time to traveling all over the country to build support for immigration reform. As a national figure, his time is in great demand. He rarely misses substantive votes and when he does, it is because he cannot be in two places at once.”

Gutierrez sporadically explains his absences — a statement for the Record in July gave a clear reason for one: He was attending oral arguments in a federal court case over immigration policy. He also missed votes due to a family medical issue, meetings at the White House and, in 2011, “my participation in a peaceful rally and protest against the current Administration’s enforcement policies against immigrant students and the families of U.S. citizens.”

Representatives’ schedules are hardly overstuffed with days spent in the House chamber. In 2014, the members of the House spent only 29 weeks in session, each of which was bookended by long weekends spent doing district work, fundraising or running for re-election. The House is not scheduled to be in session for a five-day week this year.

As lawmakers balance their duties, not every vote is created equal. Both ProPublica’s analysis and research by Eleanor Neff Powell, a political scientist at the University of Wisconsin, found that lawmakers miss more lopsided votes than ones that are important to either political party.

There have been 20 times when the number of explained missed votes exceeded the final margin of approval or defeat. Half were on amendments. One, a 2011 amendment to a spending bill about labor agreements on federal construction projects was approved by a single vote and had eight explanations from the 25 House members who did not vote, including three Republicans opposed to the amendment.

Bills that have widespread bipartisan support often are considered “under suspension of the rules,” which means they are debated fairly quickly, sometimes in a few minutes, and must have the support of two-thirds of those voting. About four in 10 personal explanations occur on these so-called suspension votes, which often are scheduled on the first day of the week that the House is in session, when travel delays could make it more likely for a member to miss votes. Absences (explained or not) on suspension votes account for 36 percent of all House votes missed between 2007 and October 2015.

If personal explanations are optional, why do representatives use them at all? Often, to indicate to constituents that just because they didn’t vote doesn’t mean they don’t have an opinion.

“It shows that you care about what they’re asking about,” said Powell.

For lawmakers facing tight re-election contests, missed votes can be part of a political balancing act. Opponents are quick to make use of a poor voting record. Missing a vote can be a graceful way to dodge votes designed to put lawmakers on the spot. Explanations, in turn, can provide a way to miss the actual vote and still claim that they would have voted the way constituents might have preferred.

In 2013, Brad Schneider, an Illinois Democrat, voted against a Republican spending bill that also delayed the individual health insurance mandate created by the Affordable Care Act. The next year, he missed a vote on a bill to delay the individual mandate but explained that, had he been there, he would have voted in favor of delaying the mandate, as he did on a similar bill in July 2013. Schneider lost his seat in 2014 to Bob Dold, a Republican former congressman who voted against the health care law while in the House, in a race where the health insurance law figured prominently. He is running against Dold again in 2016; Schneider’s campaign did not respond to a request for comment.

One of the electronic voting devices used by members to vote on the House floor. (Scott J. Ferrell/Congressional Quarterly/Getty)

Missing potentially controversial votes, then submitting explanations is an example of what researcher Powell calls “strategic abstention”: when a member skips a vote on which her party’s position is incompatible with her constituents’ views. Rather than disappoint either, the Representative can simply miss the vote, later explaining that she would have voted the way her constituents would have wanted, without actually doing so and creating a rift with her party.

The ProPublica analysis, which covers a different time period than Powell’s, found some evidence of this: there were 128 votes on bill passage in which a member who missed the vote later registered opposition to his or her party’s majority position. Fifty-six of those contained no clear reason for the absence.

Lawmakers’ explanations cover not only missed votes, but mistaken ones as well. It’s not common — explanations attempting to correct a wrong vote or saying that a member tried to vote but could not — number about 320 during the past eight years. But more than one in five current lawmakers has done it at least once since the beginning of 2007, with John Conyers, a Michigan Democrat and the chamber’s longest-serving member, claiming 12 incorrect votes. The official record of a 2011 vote on an bill to expand offshore oil and gas leases shows Conyers voting in favor, when he meant to vote against the bill. Conyers, who at 86 is also the House’s oldest member, did not respond to several requests for comment made through his office.

A handful of other lawmakers have reported voting incorrectly at least four times, including Adam Smith, a Washington Democrat who is the ranking member on the House Armed Services Committee. On at least one of those occasions, on a vote that occurred at 1:53 a.m. on Feb. 18, 2011, Smith voted for an amendment and later explained that he should have voted no. Rebecca Bryant, a spokeswoman for Smith, said that in that case the congressman “had some misinformation” on the nature of the amendment that was only clarified the next morning.

“The key thing is transparency,” said Bryant of the vote explanations. “We wanted to articulate how the congressman felt.”

Occasionally, lawmakers change their minds after a vote and submit a personal explanation about it. In 2008, the House voted to censure Charlie Rangel, a New York Democrat, over ethics violations, and Texas Republican Lamar Smith voted in favor of doing so. Later, in a statement in the Record, Smith reconsidered his vote: “Members had no advance notice of the vote, and I did not familiarize myself with the substance of the motion as much as I would have liked. If the vote were taken again, I would vote present rather than ‘aye’.”