In JD Vance, Trump has picked a mini-me offering red meat to his Maga base

He could have chosen a woman, a person of colour or a political moderate. Instead Donald Trump went for a mini-me.

The former US president announced on Monday that his running mate in the presidential election is JD Vance, a senator for Ohio and friend of his son, Donald Trump Jr. The sports arena hosting the Republican national convention erupted as Vance entered, grinning broadly and shaking countless hands as Merle Haggard’s America First played twice.

The 39-year-old arrives with the zeal of the convert. In 2016 he eviscerated Trump as “cultural heroin” and a demagogue “leading the white working class to a very dark place”. For good measure he called himself “a never-Trump guy” and wrote: “Trump makes people I care about afraid. Immigrants, Muslims, etc. Because of this I find him reprehensible.”

But the senator’s journey since then is the journey of much of the Republican party. He is all-in for the Make America great again (Maga) brand of populist-nationalism, echoing Trump on abortion, climate, election denialism, immigration and America first isolationism – a terrible blow to Ukraine. His willingness to abandon principle suggests he would not stand up to Trump in defence of democracy as Vice-President Mike Pence did in 2021.

Trump has followed the playbook of Bill Clinton, who in the 1990s chose Al Gore, a young moderate from the south like himself. Instead of seeking a complementary contrast on the ticket, Vance represents more of the same – heir apparent to a 78-year-old commander-in-chief who has already served one term.

Related: Who is JD Vance, Trump’s vice-presidential pick?

That may reflect Trump’s confidence in the Maga brand as he leads opinion polls and Democrats bicker. Back in 2016, he chose Pence because he needed to persuade Christian evangelicals that a thrice-married reality TV star with questionable knowledge of scripture was worth a shot.

Now those religious right voters are priced in, partly because Trump’s first term delivered three rightwing supreme court justices who overturned the constitutional right to abortion and partly because Democrats have been successfully demonised as godless leftwing radicals.

Still, Vance represents a gamble. For a long time the conventional wisdom held that Trump would pick a woman to combat the abortion issue and his own chequered past, including a jury finding him liable for sexually abusing the advice columnist E Jean Carroll.

A woman such as Elise Stefanik might have helped Trump close the yawning gender gap that sees him getting trounced among female voters. A Black running mate such as Tim Scott might have helped Trump bridge the racial divide that – despite recent gains – still has him losing heavily among African Americans.

Instead, a white male running mate looks like an unapologetic play for even more of his white male base. Trump understands the logic of divide and conquer better than most.

As the author of Hillbilly Elegy, a bestselling memoir about the cultural crisis of white working-class Americans, Vance also provides at least the perception of intellectual heft – and of speaking the language of blue-collar voters in the all-important rust belt.

The announcement comes at a critical moment, just two days after Trump survived an assassination attempt at a campaign rally in Pennsylvania. The former president’s instinctive response was pumping his fist and urging his supporters to “fight”.

Taking his cue, Vance tweeted soon after that shooting was not some “isolated incident” but that the Biden campaign had framed Trump as “an authoritarian fascist who must be stopped at all costs”. He added: “That rhetoric led directly to President Trump’s attempted assassination.”

Later, however, Trump appeared to shift his tone, appealing for national unity and a lowering of the political temperature. He told the Washington Examiner newspaper that he was rewriting his convention speech. “It is a chance to bring the country together,” he said. “I was given that chance.”

That would be smart politics, a chance for Trump to use a prime-time TV platform to make the right noises to independent and moderate voters in swing states. If only a small chunk buy into the narrative that his near-death experience has redefined him, that could be enough to win the electoral college.

Vance, meanwhile, can be an effective foil in the role of Trump’s attack dog, going in hard on issues at moments when he holds back. While Trump plays on the sympathy vote after Saturday’s shooting, Vance can throw red meat to the base and assure them that Maga is as extreme ever.

Related: Democrats resurface Trump VP pick JD Vance’s many criticisms of former president

That includes the issue of Ukraine. It would be politically shrewd of Trump to reassure national security Republicans that he will not raise the white flag to Vladimir Putin. But in Vance he has a senator who earlier this year voted against a supplemental aid package of more than $60bn to Ukraine – and who has declared his opposition to virtually any proposal for the US to continue funding the war.

Speaking at the Conservative Political Action Conference in February, Vance said: “I think that it is absurd for us to devote so many resources, so much attention and so much time to a border conflict 6,000 miles away when our own southern border is wide open. We’ve got to focus more on our problems close to home.”

Such statements make clear what direction the Trump-Vance ticket will take. With everything going his way, from the classified documents case to the politics of failed assassination, Trump feels emboldened to tell voters to take their Maga medicine pure and undiluted. And should he feel the need to assault democracy again, don’t expect Vance to stand in the way.