During the third and final presidential debate on 19 October 2016, Republican nominee Donald Trump remarked that President Barack Obama “has moved millions of people out … millions of people have been moved out of this country.” As of 2015, more than 2.5 million undocumented persons had been deported by immigration authorities since President Obama took office in 2009, a total which was statistically record-setting. During the two terms of Obama’s predecessor, President George W. Bush, just over 2 million people were deported.

However, that statistic is somewhat misleading, as a significant portion of it was due to a change in the way “deportations” are defined that began during the Bush administration, not in the actual number of persons turned out of the U.S. As the Los Angeles Times noted, if not for that change in definition about what constitutes a “deportation,” the Obama administration likely would not have been a record-setting one in this area:

The number of people deported at or near the [U.S.-Mexico] border has gone up — primarily as a result of changing who gets counted in the U.S. Immigration and Customs Enforcement agency’s deportation statistics. The vast majority of those border crossers would not have been treated as formal deportations under most previous administrations. If all removals were tallied, the total sent back to Mexico each year would have been far higher under those previous administrations than it is now. Until recent years, most people caught illegally crossing the southern border were simply bused back into Mexico in what officials called “voluntary returns,” but which critics derisively termed “catch and release.” Those removals, which during the 1990s reached more 1 million a year, were not counted in Immigration and Customs Enforcement’s deportation statistics. Now, the vast majority of border crossers who are apprehended get fingerprinted and formally deported. The change began during the George W. Bush administration and accelerated under Obama. The policy stemmed in part from a desire to ensure that people who had crossed into the country illegally would have formal charges on their records. In the Obama years, all of the increase in deportations has involved people picked up within 100 miles of the border, most of whom [had] just recently crossed over. In 2013, almost two-thirds of deportations were in that category.

The deportation trend abated towards the latter part of the Obama administration, with Immigration and Customs Enforcement (ICE) announcing efforts to “prioritize convicted criminals and threats to public safety, border security, and national security.” Although 2013 was a record-setting year with 435,498 deportations, 2015 saw the lowest numbers in a decade, according to ICE.

Data provided by ICE dating back to 1892 records that annual deportations jumped into the hundred-thousands in 1997, when the U.S. deported 114,432 people. Just one year earlier, the U.S. had deported only 69,680 people.

According to the non-profit immigrant advocacy group American Immigration Council, the trend in growing deportation numbers long preceded Barack Obama’s presidency:

The federal government has, for nearly two decades, been pursuing an enforcement-first approach to immigration control that favors mandatory detention and deportation over the traditional discretion of a judge to consider the unique circumstances of every case. The end result has been a relentless campaign of imprisonment and expulsion aimed at noncitizens — a campaign authorized by Congress and implemented by the executive branch. While this campaign precedes the Obama administration by many years, it has grown immensely during his tenure in the White House.

The trend can be traced back to the Immigration Reform and Control Act (IIRCA) of 1986, “which encouraged the initiation of deportation proceedings against any immigrant convicted of a deportable offense. Since that time, a stream of punitive legislation has eaten away at the traditional discretion of judges to grant relief from deportation in particular cases.”

According to the Pew Research Center, other variables have played into the climbing rate of deportations during Barack Obama’s presidency, including higher rates of apprehension by Border Patrol agents:

One distinct feature of the record number of deportations is the increasing share of deportations by U.S. Customs and Border Protection after border apprehension. In 2013, 25% of all deportations were carried out by the agency, up from 17% in 2012. Meanwhile, the number of deportations carried out by U.S. Immigration and Customs Enforcement, which deports people caught both at the border and the interior of the country, fell in 2013 compared with 2012. This rise in the number of deportations also coincides with stalled growth of the U.S. unauthorized immigrant population since 2009, and a more recent rise in the number of apprehensions at the U.S.-Mexico border. In 2013, there were 414,000 apprehensions at the southwest border, a rise of 27% over 2011 (the most recent low in apprehensions).

The Border Patrol’s budget has expanded from $5.9 billion 2003 to $11.9 billion in 2013, while ICE’s grew from $3.3 billion to $5.9 billion. As of 2013, the two agencies had a total budget of nearly $18 billion, and that number increased to nearly $20 billion in 2016.

Another factor for the increase in deportations during Obama’s terms comes from legislation that has become known as a “bed mandate” or “bed quota:”

The bed quota requires U.S. Immigration and Customs Enforcement (ICE) to hold an average of 34,000 individuals in detention on a daily basis. This quota has steadily increased since its establishment in 2009. No other law enforcement agency is subject to a statutory quota on the number of individuals to hold in detention. The bed quota prevents ICE from exercising discretion and expanding more efficient alternatives to detention (ATD) that would allow individuals who pose no risk to public safety to be released back to their families while awaiting immigration court hearings.

The Washington Post described how ICE has maintained that average of 34,000 individuals in detention and how the practice has affected the number of deportations:

The policy requires U.S. Immigration and Customs Enforcement (ICE) to keep an average of 34,000 detainees per day in its custody, a quota that has steadily risen since it was established in 2006 by conservative lawmakers who insisted that the agency wasn’t doing enough to deport unlawful immigrants. But as illegal crossings from Mexico have fallen to near their lowest levels since the early 1970s, ICE has been meeting Congress’s immigration detention goals by reaching deeper into the criminal justice system to vacuum up foreign-born, legal U.S. residents convicted of any crimes that could render them eligible for deportation. The agency also has greatly expanded the number of undocumented immigrants it takes into custody after traffic stops by local police.

The American Immigration Council explained how recent trends toward combining the duties of local law enforcement and federal immigration authorities also contributed, with programs such as the now-discontinued Secure Communities and 287(g):

Secure Communities, which was created in 2008, is an information-sharing program between DHS and the Department of Justice. The program uses biometric data to screen for deportable immigrants as people are being booked into jails. Under Secure Communities, an arrestee’s fingerprints are run not only against criminal databases, but immigration databases as well. If there is an immigration “hit,” ICE can issue a “detainer” requesting that the jail hold the person in question until ICE can pick him up. Under Section 287(g) of the Immigration and Nationality Act, DHS may deputize selected state and local law-enforcement officers to perform the functions of federal immigration agents. Like employees of ICE, these “287(g) officers” have access to federal immigration databases, may interrogate and arrest noncitizens believed to have violated federal immigration laws, and may lodge “detainers” against alleged noncitizens held in state or local custody.

Secure Communities was replaced by the Priority Enforcement Program, which prioritizes “threats to national security, public safety, and border security.”

In the 105 years between 1892 and 1997, the U.S. deported 2.1 million people — meaning that under presidents Bush and Obama, the number of people deported by the U.S. in the course of a century was more than doubled in just 16 years of consecutive presidencies.