PolitiFact last week looked at a senator's claim about how many welfare benefits go to immigrants, the president's attribution of the opioid crisis to fewer drug prosecutions, and the attorney general's linking Chicago crime to its 'sanctuary city' policing. Summaries of our findings are here. Full versions can be found at www.politifact.com.

“Half of all immigrant households receive benefits from our social welfare system.”

— Sen. David Perdue on Tuesday, Aug. 8, 2017 in a USA Today op-ed

Research has found that about 50 percent of households headed by an immigrant (living here legally or illegally) do benefit from government assistance programs. In many of those households, it’s a U.S.-born child who is eligible for a program.

Using data from the Census Bureau’s Survey of Income and Program Participation, one study found that in 2012, 51 percent of immigrant-headed households (living here legally or illegally) reported having used at least one welfare program during the year, compared with 30 percent of native-born households.

Our ruling

Research from the Center for Immigration Studies found that in 2012, 51 percent of immigrant-headed households (living here legally or illegally) were reported to have used at least one welfare program during the year. That percentage includes a broad definition of welfare, including school lunch. Excluding subsidized school lunches, welfare use for immigrant households would be 46 percent, according to the study.

Perdue’s statement is accurate but needs clarification or additional information.

We rate it Mostly True.

“At the end of 2016, there were 23 percent fewer federal prosecutions than in 2011, so (prosecutors) looked at this scourge (opioid deaths) and they let it go by.”

— Donald Trump on Tuesday, Aug. 8, 2017 in a briefing on opioids

We found Trump is correct that federal drug prosecutions declined from 2011 to 2016 under Obama, but he lacks evidence to prove that’s the culprit for the opioid crisis.

The Justice Department filed drug charges against 24,638 defendants in 2016, down 23 percent from 2011, according to the Pew Research Center, which analyzed federal data. The data reflect felonies and some serious misdemeanors. But that’s overall drug prosecutions, not just those related to opioids, and it only includes federal prosecutions. The vast majority of criminal prosecutions are in state courts.

Trump implied lack of prosecutions likely led to a worsening of the opioid crisis. But experts we contacted had a different view.

Our ruling

Federal drug charges overall declined 23 percent between 2011 and 2016. But Trump misses the mark in suggesting the drop in prosecutions is to blame for the opioid epidemic, which started before Obama’s tenure and grew worse during his presidency. Obama could have done more earlier to address the epidemic, experts said, but there is no evidence that his drug-prosecution strategy led to a spike in opioid overdose deaths.

We rate this claim Half True.

Chicago city officials “have adopted an official policy of protecting criminal aliens who prey on their own residents.”

— Attorney General Jeff Sessions on Monday, August 7, 2017 in a press release

The alleged link between illegal immigrants and surges in crime has been debunked repeatedly for decades in academic, government and advocacy-group studies. We started our look at Sessions’ statement by contacting the Department of Justice with a request for data to back up his claim.

DOJ referred us to, among other sources, a 2016 study by the Murder Accountability Project, a nonprofit group that tracks unsolved homicides and advocates better crime reporting. It showed Illinois had the nation’s lowest homicide clearance rate. But the report attributes that to record-keeping methods of the Illinois State Police in gathering crime data statewide.

Chicago Police Superintendent Eddie Johnson said in an NPR interview Aug. 7, “The vast majority of our issues in Chicago and our violent crime is committed by homegrown people … So our instances of undocumented people committing horrific crimes and murder in particular in Chicago is just — it’s nominal.”

Because its police department does not collect immigration data, the city can’t unequivocally state that its murder or gun violence rates are not attributable to immigrants. The anecdotal evidence in Chicago’s favor appears strong, but it’s still anecdotal.

Our ruling

Chicago’s sanctuary city policy does not protect undocumented people who commit crimes, despite what Sessions claims.

We rate his statement False.