The President's approval rating is down to its lowest in a year

57 per cent say that Obama is doing a bad job keeping Americans safe

National security and terrorism are now the top priorities for most Americans as the issues have catapulted themselves to the top of the political agenda, according to a new poll.

While people were most concerned about economic and job security at the start of this electoral cycle, that has now given way to fears over deadly attacks after Paris and San Bernardino.

Forty per cent of Americans now think terrorism and national security should be the government's top priority, compared with 21 per cent who thought the same back in April.

Obama's faltering response to the two atrocities has helped to slash his approval rating to 43 per cent, its lowest for almost a year, while giving his opponents the means to attack his administration.

This graph shows that in April (red) 21 per cent of Americans thought national security should be the US Government's priority - but this proportion had soared to 40 per cent by December (blue)

A total of 57 per cent of citizens believe that Obama (pictured on Monday) is doing a bad job on national security. His overall approval rating is down to 43 per cent - its lowest level for a year

Meanwhile the issue of security is expected to take center stage at the Republican debate in Las Vegas tonight as Donald Trump (pictured on Monday) once again takes center stage following his pledge to ban all Muslims from coming into the U.S.

A poll by NBC and the Wall Street Journal found that, when asked specifically about national security, 57 per cent of Americans think Obama is doing a bad job.

That is despite the poll being carried out between December 6 and 9, the three days immediately after Obama's Oval Office address to the nation, which was designed to alleviate those fears.

The poll also revealed that 42 per cent of Americans think the strategy against ISIS should involve both airstrikes and American ground troops, a stance strongly opposed by Obama.

Even more dramatic is the seven in 10 Americans who now think the country is headed in the wrong direction and needs to get back on track.

Democratic pollster Fred Yang said: 'For most of 2015, the country's mood, and thus the presidential election, was defined by anger and the unevenness of the economic recovery.

'Now that has abruptly changed to fear. [That leads to] a very different campaign than the one we thought we'd be running.'

Back in April, when asked what the most pressing issue facing the U.S. is, 29 per cent of those polled put job creation and economic growth as their top priority.

By contrast, national security and terrorism was chosen as the top priority by 21 per cent of people surveyed that month.

Asked to break down their concerns over security, Americans said their biggest fear was still the Paris bomb and gun attacks which saw 130 people killed by terrorists who had returned from Syria. Above is a makeshift memorial to the victims in Paris

Second on the list of security concerns for U.S. citizens were the attacks in San Bernardino which saw Syed Farook and wife Tashfeen Malik (pictured) kill 14 before being shot dead by police

When asked the same question in December, fears over the economy was named as the top priority by just 23 per cent of voters.

Meanwhile, terrorism and national security had catapulted itself to the top of that list, being named as the number one priority by 40 per cent Americans.

Separately, a poll carried out Gallup released yesterday showed that terrorism is the most pressing issue on people's minds, with 16 per cent saying it is the most important issue facing the country.

That chimes with a New York Times/CBS poll last week found that 79 per cent of Americans believe a terrorist attack is somewhat likely or very likely in the next few months.

It is a fear that is being capitalized on by politicians such as Donald Trump, who has called for a ban on all Muslims coming to the U.S. following the San Bernardino attack in which 14 people died.

While many of Trump's rivals have forcefully condemned the idea, Ted Cruz has been more mute in his criticisms, while his poll ratings have slowly increased.

For the first time, the issue is expected to dominate the Republican debate due to take place in Las Vegas tonight, showing how the political landscape has shifted from the last debate a month ago.

It is also changing the debate on the Democratic side of the field as well, with Hillary Clinton vowing to go further than Obama in her moves to combat the likes of ISIS.

The Democratic frontrunner is also expected to give a speech on the issue later today.

Highlighting these fears is the ongoing situation in Los Angeles, where all schools have been shut down due to a 'credible terrorist threat', according to area superintendent Ramon Cortines.

Highlighting those fears, schools across Los Angeles were closed today and being searched by the FBI and police after a suspected terror threat

A thousand schools were closed (above) and 640,000 children kept at home today after a threat believed to have involved backpack bombs was received, while schools in New York were also threatened

More than 640,000 children are urged to stay in their homes amid fears of an attack on the nation's second largest school district.

The FBI and explosive experts have been called in to sweep every locker, classroom, office, and bathroom of every campus across the 5,000-square-mile county.

Asked to break down their fears around security, Americans said their top concern is still the bomb and gun attacks in Paris which saw 130 people killed by terrorists who had come to the country from training camps in Syria.

Second was the shooting in San Bernardino attack, carried out by U.S. born radical Syed Farook and his wife Tashfeen Malik who had recently moved to America from Saudi Arabia.

But third on that list, and polling almost equal with the San Bernardino attack, was concerns around random mass shootings such as those carried out by Dylan Roof in Charleston, or at Umpqua Community College by Christopher Harper-Mercer.

Astonishingly, more than seven in ten respondents said that such attacks have now 'become a permanent part of American life'.

That will raise issues for Republicans who have almost universally resisted calls for tighter gun laws in the wake of such attacks, with Cruz even attending a gun rally two days after San Bernardino.