Has Newsom got what it takes to challenge Trump?

Sixty years is a very, very long time in fast-moving US politics. But that is how long ago it is since a US president ordered the national guard into a state without a request from the state governor. The line between federal and state-level law enforcement is one of the many very clear demarcations of authority in the US federal system. It is another hallowed line that Donald Trump has crossed. From a purely public order standpoint, Trump's dispatch to Los Angeles of a 4,000-strong contingent from the national guard, bolstered by 700 US marines, appears to be having the intended effect.

The violent protests that erupted in response to the efforts of Immigration and Customs Enforcement (ICE) agents to detain and deport people with no legal right to be in the United States have died down. Order has mostly been restored, and thousands are under arrest — whether for immigration violations, for violence, or for defying the city-imposed curfew.

Smaller protests that subsequently broke out in other cities also appear to have been discouraged by Trump's characteristically unsubtle — and constitutionally contestable — application of presidential power. If the short-term effect looks close to being an unqualified success from the perspective of the White House and Trump's political base, there has to be a question, indeed several questions, about the longer term.

How likely is it that the president's actions are storing up liabilities, either for him or his political heirs? One immediate effect has undoubtedly been to propel California's governor, Gavin Newsom, into the limelight again as a leader of the state-level opposition to Trump, as he became in Trump's first term. And it has to be said that the Democrats are in sore need of such leadership.

Far from being energised by Kamala Harris's defeat, to refresh their party and rally around a new leader, Democrats have seemed at a complete loss as to how to combat the second-term Trump.

Could the Democrats now find a new champion in Gavin Newsom - and is he equal to the task? Might he even be able to exploit his stand-off with Trump to become a plausible presidential contender for 2028? He certainly seems up for the challenge.

Having said after Trump's victory — to the distress of some supporters — that he would work with the second-term president, Newsom has come out fighting over the ICE raids on illegal migrants and has threatened to sue through the courts over the deployment of the national guard. And whereas the last time the national guard was sent into a state without the governor's say-so - to protect civil rights protesters in Alabama — there was an element of covert politicking, there is nothing of that this time around.

An argument can — and doubtless will - be made that immigration enforcement is a federal responsibility; that the ICE agents met violent resistance and that they required protection that the city of Los Angeles and the state of California either would not (or could not) give. Whether that justifies federal intervention, however, is a matter that may well be decided in court.

So long as the national guard operate within their lawful parameters, which appears to be the case - and so long as the marines are not used to keep civil order, but only to protect the national guard - there may be no case for Trump to answer.

What's more, however much Trump's opponents might like to present him as riding roughshod over states' rights to assert federal control, this is not entirely true either. The Supreme Court's overturning of Roe v Wade on abortion rights, which was lauded by Trump, was as much of a reassertion of states' rights as a rolling back of the rights of women.

A win on the issue of states' rights would undoubtedly project Newsom on to the national stage. Even then there could still be a question about his prospects of rising to lead a coherent Democratic Party opposition to Trump more broadly. Yes, he was a contender to become Kamala Harris's running mate - had an all-California ticket not been judged a potential liability (which, of course, it was). Yes, he became a thorn in the side of the first-term Trump on a host of issues. And yes, Ronald Reagan made the governorship of California a stepping stone to the presidency. But that might not be enough.

Newsom has provoked vocal opposition within his own majority Democrat state, and there is little doubt that Trump would be up for a fierce rhetorical and political fight in defence of his programme. He has shown little but contempt for Newsom hitherto, whom he sees as left, liberal and weak, with an insatiable appetite for high taxes. He is to the great detriment, as he sees it, of California's wellbeing (a one-person equivalent, in a way, of Trump's other object of hatred, the EU). Many of Trump's loyal base will be of like mind.

Then again, even if Newsom were to emerge as a politician capable of arguing the Democrat cause on the national stage, there are compelling reasons why this particular stand-off might not work in his favour in the bigger scheme of things.

The problem for Newsom is that, even as Trump has been losing support nationally on other issues, support remains strong for his tough stance on migration. Appearing to support illegal aliens to remain in the US is probably not a hill Democrats will want to die on, either now, in the run-up to next year's midterm congressional elections, or in 2028.

Trump may also be less vulnerable than many previous presidents to party political opposition. There is some new talk of impeachment (already), but he saw off two attempts before, and anyway, electorally, as a second-term president, he has little to lose, for all the loose talk he might try to change the constitution to make possible a third term.

The awkward reality is that Republicans running for office are more dependent on him, than he is on them. Added to which, Trump is not a party creature. He is a one-off deal-maker turned president, who is testing constitutional power to its limits.

His Republican badge is a flag of convenience, required by the political system. Traditional Republicans may be counting the days until their party can nominate a real, more predictable, Republican for the highest office. In the meantime, their political fortunes are tied to his, and his sights are set on what he will bequeath, which includes a country with fewer illegal migrants, where America - in his definition - comes first. Gavin Newsom may have a national future; but he might do well to rein in his fury and bide his time.