Media playback is unsupported on your device Media caption Donald Trump's new television advert uses footage reportedly taken in Morocco

Donald Trump is taking to the television airwaves, and his first advert prominently features his controversial call for temporarily halting the entry of all Muslim into the US and a border wall "paid for by Mexico".

The 30-second spot is narrated by a stern-sounding male voice and features grainy images of Democrats Hillary Clinton and Barack Obama.

The advert also includes photos of the San Bernardino attackers, so-called Islamic State militants, a US warship firing cruise missiles, exploding buildings and undated footage of migrants purportedly crossing the US-Mexican border.

The commercial concludes with Mr Trump offering his trademark call to "make America great again", delivered before a cheering crowd.

It wouldn't be Trump without some measure of controversy, of course. The fact-checking website Politifact says the border video is actually from Morocco - and the Trump campaign has since said the use of the footage was intentional and that it was what the US border could eventually look like if it is not adequately secured.

Up until now, Mr Trump has maintained his position at the top of presidential preference polls thanks to his seemingly unique appeal to a blue-collar segment of the Republican electorate, buttressed by near-nonstop news media coverage of his non-traditional campaign and his often controversial comments.

Mr Trump, in a news release announcing the advert, said that his campaign is currently $35 million (£24 million) "under budget". He added that he wasn't sure he needed to spend money on television commercials, but "I don't want to take any chances".

While Mr Trump spent about $300,000 on three radio adverts last fall, the release says his new television campaign will cost about $2 million (£1.4 million) a week in the early voting states of Iowa and New Hampshire.

According to a recent report in the New York Times, however, the Trump campaign has yet to reserve airtime in either state - which casts some doubts about the actual size of the advertising purchase.

What's clear, however, is that Trump's video has once again made him a top story in the political media, generating yet another wave of free publicity.

His campaign gave the Washington Post a sneak preview on Sunday, leading to a 1,300-word article that featured Mr Trump talking about the details of the advert design, including his preference for using campaign rally footage instead of the more traditional, candidate-talks-to-the-camera style.

"I don't like sitting down and shooting an ad because I don't think you capture the same energy you see at our events," he said.

The content of the advert has some analysts scratching their heads, however. According to the Atlantic's David Graham, a new television campaign traditionally aims to appeal to voters not already in the candidate's camp.

"If the point of these ads is to win over new voters, is a recap of months-old messages the most effective way to do it?" he asks.

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Even if the advertising purchase does total the $2 million a week that Mr Trump promises, that will - at best - only put him on roughly equal footing with competing candidates in terms of paid media over the coming weeks. A group supporting Texas Senator Ted Cruz has announced a $4 million buy over the coming weeks, for instance, and a political action committee tied to former Florida Governor Jeb Bush's campaign has reserved more than $19m in airtime between now and February.

Of course, the Bush team has already spent more than $41 million on television advertising, and yet his poll numbers continue to sag. Ohio Governor John Kasich and his affiliated groups have spent $9 million, almost exclusively in New Hampshire, and after an early surge in there, he's now mired in single digits - well behind front-running Trump.

According to NBC News, presidential candidates spent almost $120 million combined on television advertising in 2015, with Mr Trump accounting for only the smallest fraction of that.

Television advertising, at least this election, may be overrated. It seems, however, that Mr Trump has decided it's a game he needs to play.

Republican candidates in, and out, of the 2016 presidential race