It's Trump-Pence! The Republican ticket is made

Three days before the convention, the Trump-Pence bumper stickers are rolling off the printers

Trump and Pence appearing together earlier this year in Indiana (AP)

Donald Trump ended any lingering suspense over his choice of running mate, saying in a Twitter message that he had settled on Mike Pence, the 57-year-old Governor of Indiana, who is one of the Republican Party’s most staunch social conservatives with a record of resisting the expansion of gay rights and restricting access to abortion for women.

"I am pleased to announce that I have chosen Governor Mike Pence as my Vice Presidential running mate," Mr Trump declared.

It is surely the first time that an American vice presidential pick has been confirmed via social media. However, the original plans for Mr Trump to announce his decision and introduce Mr Pence at a press conference in New York on Friday morning were shelved by the candidate himself late on Thursday evening because of the Nice lorry attack.

Mr Trump said that he will now hold a press conference in New York alongside Mr Pence to trumpet his decision on Saturday morning. Unusually, it will not take place at one of his own properties in the city but at the Hilton Hotel in Midtown Manhattan.

The choice of Governor Pence, a one-time radio talk show host and a six-term member of the US Congress, and even the decision not to showcase one of his own properties for the announcement offer further evidence that Mr Trump his heeding the advice of senior party members and beginning to adopt a more conventional campaign style.

As if often the case in these running mate selections, geography matters. Mr Pence comes from the crucial Midwest, an electorally crucial region and a part of the country where Mr Trump is appealing to white male voters dismayed by the draining away of jobs from rustbelt cities. Indiana itself is likely to be a swing state in November.

(Donald Trump campaign (Donald Trump campaign)

His presence on the ticket will reassure conservative Republicans who have voiced suspicions that Mr Trump is not really one of them. But his hardline positions on abortion and gay rights may not help Mr Trump win over more progressive independent voters.

A self-described Christian evangelical, Mr Pence once said that he considered himself as “a Christian, a conservative and a Republican, in that order”.

Last year, Mr Pence signed a highly controversial religious freedom law to allow private businesses to deny service to any individuals if they thought to do so would violate their religious beliefs. The law was widely seen as an attack on the LGBT community, however, and he was forced to seek a rewriting of the law in the face of threats of a boycott against his state.

He eventually won the contest to be Mr Trump’s running mate against competition in particular from the former House speaker, Newt Gingrich, and the serving Governor of New Jersey, Chris Christie. The latter stunned his own party by first dropping out of the nomination and then being the first among members of the party establishment to endorse Mr Trump’s run for president.

In the end, however, it appears that Mr Trump opted not for someone who could work as his attack dog – a role to which Mr Christie would have been especially suited - but instead for a person known for his even demeanor and unflappability.

Among the best-known quotes attributed to Mr Pence is the one where he said: "I'm a conservative. But I'm not angry about it.” In other words, if Mr Trump is known for being impulsive and occasionally shooting from the hip – especially on Twitter and at the podium at his often rambunctious rallies – Mr Pence is regarded as someone with a very even keel.

“One thing you can say about Mike Pence is he's got a very calm, steady demeanor that in some ways is a little Reaganesque,” said Christine Mathews, a Republican pollster for former Indiana Governor Mitch Daniels. “He's a counterbalance to Trump in that way.”

Some might have expected Mr Trump to find a political outsider such as himself or perhaps a military figure to bolster his slender national security credentials. The choice he eventually made was praised by Reince Priebus, the chairman of the Republican National Committee, who says Mr Pence offered a “very different style that I think shows a lot of maturity” on Trump's part”.

Paul Ryan, the House speaker who has been half-hearted in his embrace of Mr Trump, extolled the choice of Mr Pence, saying “we need someone who is steady and secure in his principles, someone who can cut through the noise and make a compelling case for conservatism”.

Perhaps predictably, however, Hillary Clinton’s campaign quickly seized on the more extreme conservatism displayed by Mr Pence as Governor. Campaign chairman John Podesta called him “an incredibly divisive and unpopular figure”, known for supporting “discriminatory politics and failed economic policies that favor millionaires and corporations over working families”.