President Barack Obama's Republican adversaries piled on the criticism on Friday after he turned the overnight Dallas police massacre into a political platform – and then grinned from ear to ear as he reconnected with world leaders at a NATO summit in Poland.

Obama and British Prime Minister David Cameron, both on their way out of office soon, seemed in a particularly light-hearted mood despite the day's grim and dominant subject matter.

The pair laughed and joked with fellow leaders as they posed for a group picture and yukked it up as photographers kept snapping.

Hours earlier Obama had sermonized about the deaths of five police Texas police officers upon landing in Warsaw, saying that 'when people are armed with powerful weapons, unfortunately it makes it more deadly and more tragic.'

'And in the days ahead we are going to have to consider those realities as well.'

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David Cameron and Barack Obama seemed cheerful as they prepared to get down to business at the NATO summit in Warsaw – but Americans remained in shock after five police officers were gunned down in Dallas

A gunman named Micah X. Johnson was killed after a four-hour standoff with police, but not before he told a hostage negotiator that he wanted to kill white police officers

The two leaders did not seem to have tragedy on their minds

'Now is definitely not the time to get political,' Dr. Ben Carson said on Fox News. 'Now is the time to use logic and ask ourselves, "Why do we have a Constitution? Why do we have a Second Amendment?"'

Retired surgeon Ben Carson, a former Republican presidential contender and current Donald Trump cheerleader, lit into him within hours and dismissed renewed calls for gun control legislation.

'Now is definitely not the time to get political,' Carson said on the 'Fox & Friends' program. 'Now is the time to use logic and ask ourselves, "Why do we have a Constitution? Why do we have a Second Amendment?"'

'They’re always saying, "You don't need a high powered weapon to hunt deer",' Carson continued. 'The Constitution is not about deer hunting. It's about people being able to defend themselves from an overly aggressive government or an external invasion.'

Carson told the Fox audience that if he were president, he would ask Americans instead to 'imagine 24 or 48 hours with no police – what would your life be like?'

Thursday night's murders followed two high-profile shooting deaths of black men by police in Louisiana and Minnesota. One officer was white, the other Asian-American.

'Yes, there are some bad apples,' Carson acknowledged. 'And yes, we will find ways to deal with them. But in no way do we indict the entire police force.'

'But I guess the real issue,' he huffed, 'is – you know, the president's going to start saying, "See, gun control!"'

Meanwhile on MSNBC's 'Morning Joe,' Texas Republican Rep. Pete Sessions – another Trump backer – attacked Obama for exhibiting 'weakness' by not being at home in the U.S. while the dust settled on a national tragedy.

Obama also joked with NATO secretary general Jen Stoltenberg while other world leaders looked on

Former Gov. Mike Huckabee dismissed Obama as a wedge-issue divider for pushing gun control 'at a time of great grief'

The Dallas gunman has been identified as 25-year-old Micah Xavier Johnson of Mesquite, Texas, a Black Panther sympathizer who said his aim was to kill white cops

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William Johnson, the executive director of the National Association of Police Organizations, said Friday that America is in 'a war on cops, and the Obama administration is the Neville Chamberlain of this war'

'If we are weak at home, we are weak around the world,' Sessions said. 'And this is an example of a weakness, when our president goes overseas and has a terrible tragedy like this.'

Mike Huckabee, another former GOP White House hopeful who served as govenror of Arkansas, said on 'Fox & Friends' that if the Dallas bloodbath is Obama's 1984 'Challenger' disaster, his manner of response was far behind President Ronald Reagan's.

'He doesn't need to inject the divisive arguments like gun control at a time of great grief for the nation,' Huckabee boomed.

'And he ought to do for us what Ronald Reagan did after the Challenger disaster, and that's remind us of what we have in common, not what separates us.'

'And that's why I'm always so frustrated,' he added. 'Barack Obama has such great potential to be a leader.'

Moments later Darryl Glenn, a retired U.S. Air Force lieutenant colonel who is the GOP's Senate nominee in Colorado this year, warned Obama 'not to get too far ahead of the facts ... [and] not to drive your policy agenda' on the back of a gut-wrenching tragedy.

'If we are weak at home, we are weak around the world,' Texas Rep. Pete Sessions said on MSNBC, 'and this is an example of a weakness, when our president goes overseas and has a terrible tragedy like this'

'You're going to exacerbate the issue by driving a wedge, especially a wedge between law enforcement and the people that they're there to protect,' Glenn cautioned.

Also on Fox, the executive director of National Association of Police Organizations said law enforcement officers feel 'increasingly under siege and targeted,' and blamed Obama.

'It's a war on cops,' said the NAPO's William Johnson, 'and the Obama administration is the Neville Chamberlain of this war.'