WASHINGTON (NYTIMES) - The declarations of political war started coming fast as US President Donald Trump stepped to the podium in the Rose Garden of the White House on Saturday evening (Sept 26) to announce his nomination of Judge Amy Coney Barrett to the Supreme Court.

By the time she had finished her speech accepting the nomination, less than 30 minutes later, more than a dozen groups supporting and opposing her nomination had announced, or were poised to announce, advertising and grassroots advocacy campaigns that were expected to bombard airwaves, Facebook feeds and Senate inboxes.

If activists' fervour and spending commitments hold, the battle over Ms Barrett's nomination could near US$40 million (S$55.06 million) in spending - and potentially much more - and help define the final five weeks of the presidential campaign between Mr Trump and Mr Joe Biden.

The goal is ostensibly to try to shape the Senate vote on Ms Barrett's nomination but, barring some unforeseen development or revelation, there is little expectation that Democrats will be able to stop the Republican-controlled Senate from confirming the judge, who has served on the US Court of Appeals for the 7th Circuit since November 2017.

Still, partisans on both sides have not made a secret of their plans to use the confirmation fight for political gain.

For Democrats, it is a chance to rally their base, and donors, by highlighting the suddenly very real prospect of a Republican president and Senate delivering a long-lasting conservative Supreme Court majority that could strike down some of the hardest-fought victories of the last half-century, including the Affordable Care Act and the right to an abortion.

For Republicans, it represents an opportunity to secure support from leery conservatives who may have drifted from Mr Trump, and to energise core parts of the Republican base - including evangelical and Catholic voters - by elevating issues of religion and accusing Democrats of religious intolerance for opposing Ms Barrett, an observant Catholic who is a member of a self-described charismatic Christian community called People of Praise.

Leading Democrats and their allies have signalled that they intend to steer clear of personal criticisms of Ms Barrett, eager to avoid a conservative backlash like the one that emerged in response to Democratic questioning during her 2017 Senate confirmation hearing.

During that hearing, Senator Dianne Feinstein of California, the ranking Democrat on the Judiciary Committee, told the judge that "the dogma lives loudly within you." A repeat, Democrats fear, could hurt Mr Biden, a Catholic himself who openly discusses his faith and hopes to win over Catholic voters despite Mr Trump's strong performance with them four years ago.

Mr Biden's allies have mostly approached the subject more cautiously and obliquely, raising Ms Barrett's religious beliefs primarily in the context of her jurisprudence and her associations.

The Democratic super PAC American Bridge, which has through Sunday spent more than US$36 million opposing Mr Trump, released an opposition research file highlighting Ms Barrett's affiliations with religious conservative groups that oppose abortion rights.

The file included the false claim that she was a member of a Trump-allied conservative legal non-profit group called the Thomas More Society, which is suing to block Democratic cities from accepting private funds to administer elections during the pandemic, arguing it would help Mr Biden's campaign. (American Bridge removed the claim that Ms Barrett was a member of the Thomas More Society after being asked about it by The New York Times.)

The research file also highlighted a scholarly paper Ms Barrett helped to write in the late 1990s about how the Catholic Church's campaign against capital punishment "puts Catholic judges in a bind" between their oath to enforce the death penalty and their obligation "to adhere to their church's teaching on moral matters."

But some Democrats have been more pointed in calling attention to Ms Barrett's faith. Ms Katie Hill, a former congresswoman from California who runs a political action committee supporting Democratic women, wrote on Twitter last week that Ms Barrett "comes from a religion that is straight out of 'The Handmaid's Tale'" - the dystopian novel and television series about a totalitarian state that has overthrown the US government - "because of course she does," adding an expletive for emphasis.

Ms Hill said in an email on Sunday that her political action committee, HER Time, was working to rally opposition to Ms Barrett's confirmation, and that questions about whether the judge "will impose her faith on the American people" were fair game.

"Someone's religion is important when their religious beliefs are part of the way they make decisions that come before that court," Ms Hill said, accusing Ms Barrett of holding "anti-women, anti-LGBTQ positions, which are rooted in her religion" and saying they would "factor into her decisions on the court."

Republicans have eagerly highlighted similar attacks, as well as examples of liberals scrutinising Ms Barrett's family - she has seven children, including two adopted from Haiti.

Mr Trump, at a White House news conference on Sunday afternoon, accused Democrats of "really brazenly attacking Judge Barrett for, again, her faith."

Singling out Ms Feinstein, the president said, "I think they ought to treat religion with much more respect."

The anti-abortion group Susan B. Anthony List on Saturday evening began a digital advertising campaign featuring a one-minute video that calls attention to Ms Barrett's legal bona fides and religious background, and accuses Democrats of "attacking her faith." The ad is part of what the group says will be "a seven-figure investment" supporting Ms Barrett's confirmation.

The White House has encouraged social and religious conservative groups to focus on Ms Barrett's personal life in their campaigns supporting her confirmation.

During a private conference call with more than 500 representatives of social and religious conservative groups an hour after her Rose Garden speech, senior White House staff members emphasized her family and pointed out social media posts from Republicans that did the same, including a tweet from Governor Brian Kemp of Georgia, praising her devotion to "faith, family, and the US Constitution."

Mr Douglas Hoelscher, the director of the White House's office of inter-governmental affairs, urged the groups to pull out all of the stops in support of a frenzied push to speed the nomination through the Senate in the weeks before Election Day.

"We really appreciate our stakeholders already rolling up their sleeves and engaging to have their voice added to a positive echo for the president's nomination of Judge Amy Coney Barrett," Mr Hoelscher said. "We will come back to you to help us along the way over the next month." He added, "We need to have your voice in the fight and we know you're ready for that fight."

Allied groups on the Democratic side are no less ready.

About two minutes into Mr Trump's introduction of Ms Barrett, the liberal group Demand Justice sent an email to its supporters urging them to "chip in immediately to put pressure on Senators to vote NO on confirming Amy Coney Barrett."

The group pledged last week to spend US$10 million to try to block the confirmation of any justice before the presidential inauguration in January, and to target vulnerable Republican senators who support such a nomination.

Even before the death of Justice Ruth Bader Ginsburg created the Supreme Court vacancy, Demand Justice had begun a US$2 million digital advertising campaign in July, trying to elevate the court as an issue in competitive states in the presidential race.

Those ads are unlikely to focus on Ms Barrett's religious beliefs, according to Mr Brian Fallon, the group's executive director. He issued a statement last week saying that his group had "zero interest" in raising questions about the nominee's Catholic faith.

On the right, the planned campaigns by Mr Trump-allied groups to defend Ms Barrett will be expensive.

The Republican National Committee said on Saturday that it was kicking off a US$10 million effort, which will include a digital ad campaign and a get-out-the-vote operation that the party's chairwoman Ronna McDaniel said would "aggressively promote the qualifications of Judge Barrett, and use the issue to galvanise voters."

America First Policies, a nonprofit group started by allies of Mr Trump, on Saturday night announced national television, digital and direct-mail advertising buys of more than US$5 million.

The first television advertisement in the group's campaign, featuring praise for Barrett from the faculty at Notre Dame Law School, where she is a professor, is set to air on Tuesday during the first debate between Mr Trump and Mr Biden.

Mr Brian Walsh, the group's president, said the US$5 million was the group's starting point, and that it was prepared to spend more if necessary. He emphasised the importance of introducing Barrett to the country "on our terms."

Privately, conservative activists concede that the push to support Ms Barrett stands little chance of affecting the outcome, since there are few senators whose votes are seen as being in play and whom conservatives believe they can effectively sway to vote yes.

Few, if any, Democrats are likely to support the nomination, and a campaign targeting Republicans like Senator Susan Collins of Maine, who has said she opposes filling the vacancy before the election, could backfire by further endangering her chances of winning another term and Republicans' hopes of holding onto the Senate.

During the earlier battles over the confirmations of Justices Brett Kavanaugh and Neil Gorsuch, control of the Senate was not hanging in the balance. Conservative activists said that with so much on the line now, they would have to take a more targeted and cautious approach.

For some groups, the spending on the nomination fight might have an added tax benefit, helping them fulfill requirements that they spend more than half of their annual budgets for purposes other than partisan politics. Ads about the Supreme Court could qualify as nonpartisan, even if they come across as supporting one party or the other.

In the videoconference, Mr Casey Mattox, Americans for Prosperity's vice-president for legal and judicial strategy, urged activists to act quickly "because this is going to be a pretty compressed time frame as we go through this process."

He added, "We don't have a lot of time with a nomination like this."