The National Rifle Association has become politically toxic in Washington, with even President Trump chiding lawmakers this week as afraid to buck the powerful Second Amendment rights organization.

But the true extent of the NRA’s power remains a source of contention as Congress begins another gun control debate. Gun control groups, their Democratic allies in Washington and now even Mr. Trump say they must battle the group’s approach.

The NRA’s fabled influence has drawn criticism from both sides. Senate Minority Leader Charles E. Schumer, New York Democrat, said the organization has Republicans in a “grip lock.”

Rep. Scott Taylor, Virginia Republican, said the NRA became the “boogeyman” after the killing last month of 17 people at a Parkland, Florida, high school.

“We have to elect candidates that are not funded by the NRA,” Hollywood analyst Chelsea Handler tweeted. “It is disgusting how many times this has happened, and Republicans do nothing. You all have blood on your hands.”

But the electoral scorecard shows that the NRA represents many people and is effective.

Measured by money and candidates, the NRA ranks among the most successful lobbying groups. Its candidates prevailed in 73.3 percent of the 2016 races where the NRA picked sides, and when judged by spending, 94.4 percent of the organization’s political money went to successful candidates.

But claims about the NRA’s spending often outstrip the reality.

“It’s kind of hard to nail down an exact number for any of these groups,” said Brendan Quinn, a spokesman at the Center for Responsive Politics that runs OpenSecrets.

In November, OpenSecrets issued a press release proclaiming that NRA spending had “surged $100 million amidst pro-Trump push in 2016.” Yet it turns out the $100 million figure reflects the jump in the NRA’s entire budget, meaning salaries, rent, cars, insurance, equipment, political campaigns — everything.An OpenSecrets bulletin last month showed 2016 Democratic presidential nominee Hillary Clinton collected more money from gun control groups than Mr. Trump received from gun rights groups.The NRA concedes that it spent more than ever before on presidential and congressional races in 2016, but the final tally wasn’t anything close to $100 million, according to federal documents.Probably the best available figure for the NRA’s spending in 2016 is $58.5 million, Mr. Quinn said. That total represents the sum of the NRA’s direct contributions ($1.1 million), lobbying ($3.1 million), and “outside expenditures” ($54.4 million).That year, the biggest spending group was the liberal political action committee known as Priorities USA, with reported spending of $133.4 million.The NRA’s political spending has always leaned conservative, but that slant has become much more pronounced since President Obama was in office. In 2010, for instance, the gun rights group had its biggest year in terms of direct contributions, doling out $1.4 million, records show. That money was split 73 percent to 27 percent in favor of Republicans. In 2016, on the other hand, 99 percent of the NRA’s $1.1 million contributions went to Republicans.Nor is the NRA one of

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