Make America Great Again Inc, a super PAC backing Trump, said on Sunday it was pulling anti-Biden television ads that had been set to run in the battleground states of Arizona, Georgia, Nevada and Pennsylvania and replacing them with an ad attacking Harris, Reuters reports.

The 30-second ad accuses Harris of hiding Biden’s infirmity from the public, and it seeks to pin the administration’s record solely on her. “Kamala knew Joe couldn’t do the job, so she did it. Look what she got done: a border invasion, runaway inflation, the American Dream dead,” the narrator says.

Trump, known for using insulting and sometimes offensive language to attack his opponents, gave supporters at a rally in Michigan on Saturday a taste of the insults he is likely to fling at Harris in the coming days.

“I call her laughing Kamala. You ever watch a laugh? She’s crazy. You can tell a lot by a laugh. She’s crazy. She’s nuts,” he said.

Trump will try to show swing voters that his likely new rival has her fingerprints all over two issues he is counting on for victory in November: immigration and the cost of living, Reuters reports.

Sources within the Trump campaign told Reuters it will cast Harris, the likely Democratic candidate after President Joe Biden quit the race on Sunday, as the “co-pilot” of administration polices it says are behind both sources of voter discontent.

Sources told Reuters that Trump’s campaign had for weeks been preparing for Harris should Biden drop out and she win her party’s nomination.

“Harris will be easier to beat than Joe Biden would have been,” Trump told CNN shortly after Biden’s announcement on Sunday. Trump’s campaign has signaled it will tie her as tightly as possible to Biden’s immigration policy, which Republicans say is to blame for a sharp increase in the numbers of people crossing the southern border with Mexico illegally.

The second line of attack will revolve around the economy. Public opinion polls consistently show Americans are unhappy with high food and fuel costs as well as interest rates that have made buying a home less affordable.

“She’s the co-pilot of the Biden vision,” said one Trump adviser, speaking on condition of anonymity during last week’s Republican National Convention, where a unified party anointed Trump as its nominee in the White House race.

Key Democrats believe Harris would benefit from what some call a “mini-primary”, the Associated Press is reporting, saying, “They argue a fast primary campaign would showcase to the American people, party donors and skeptics that Harris is best for the job, and give would-be contenders a chance to compete — or at least debut as potential running mates.”

Harris was making calls late in the day to congressional lawmakers and gain support, including from Representative Annie Kuster of New Hampshire – the chair of the New Democrat Coalition, a moderate caucus on Capitol Hill – who endorsed Harris Sunday.

Harris and Senate Majority Leader Chuck Schumer spoke Sunday afternoon, the AP reports, citing a person granted anonymity to discuss the private conversation.

In Harris’s statement announcing that she would be running for the nomination, she referenced Project 2025.

“I will do everything in my power to unite the Democratic Party — and unite our nation – to defeat Donald Trump and his extreme Project 2025 agenda,” Harris said.

If you are not across Project 2025, it is a roadmap for a potential second Trump presidency that details – across more than 900 pages – how Trump and his allies could dismantle and disrupt the US government. It suggests ridding the federal ranks of many appointed roles and stacking agencies instead with more political appointees aligned with and more beholden to Trump’s policy prescriptions.

Led by the rightwing Heritage Foundation, the project showcases a federal government that cracks down intensely on immigration, vanquishes LGBTQ+ and abortion rights, diminishes environmental protections, overhauls financial policy and takes aggressive action against China.

Here is an explainer by my colleague Rachel Leingang:

Democrat strategists and journalists are reporting that the money raised by Democrat donors on liberal political action committee ActBlue in the hours since Biden announced that he was dropping out of the race and named Kamala Harris as his pick for nominee has now passed $60 million. The Guardian has not verified this independently.

ActBlue has not announced a new figure yet, since saying that $46.7m had been raised since 9pm ET – a figure it said was the highest of the 2024 campaign so far.

Joe Biden’s official campaign website, joebiden.com now redirects to an ActBlue donations page.

The New York Times reports that donations have passed $50 million. The only other day where $50m was raised in a single day was after Ruth Bader-Ginsberg died, Democrat pollster and strategist Matt McDermott said on X earlier – the Guardian has not confirmed this independently.

Hello and welcome to the Guardian’s live US politics coverage following President Joe Biden’s announcement that he will be withdrawing from the race – but seeing out his term as president – and his endorsement of his Vice President, Kamala Harris.

“I will do everything in my power to unite the Democratic Party — and unite our nation – to defeat Donald Trump and his extreme Project 2025 agenda,” Harris said in a statement announcing that she would be running.

Harris reportedly sent a fundraising email that began, “I am running to be President of the United States”.

Democrat donations spiked sharply following Biden’s announcement. The liberal political action committee ActBlue announced that Democrats had donated $46.7m in the seven hours since Biden announced that he would withdraw to 9pm ET, saying it was the biggest fundraising day of the 2024 election cycle.

Reports emerged later that the total had ticked over to $50m – making it one of the two biggest fundraising days in the history of the PAC, with the other being after Supreme Court Justice Ruth Bader-Ginsbgerg died.

Meanwhile senior Democrats, including some of those who have been named as possible contenders for the presidential or vice-presidential nomination, endorsed Kamala Harris for the nomination on Sunday within hours of Biden’s announcement.

Shortly after Biden stepped aside he firmly endorsed Harris, who would make history as the nation’s first Black and South Asian woman to become a major party’s presidential nominee. Other endorsements flowed from Bill Clinton and Hillary Clinton, the first major female presidential nominee, and prominent US senators, a wide swath of House representatives and members of the influential Congressional Black Caucus.

Among top potential contenders, the governors Gavin Newsom of California, Josh Shapiro of Pennsylvania, Transportation secretary Pete Buttigieg, and Roy Cooper of North Carolina all endorsed Harris on Sunday. New York Congresswoman Alexandria Ocasio-Cortez also endorsed Harris, after holding out against calling for Biden to resign.

Donald Trump heaped scorn on Biden, saying he “was not fit to run for president, and is certainly not fit to serve”. Top Republicans in Congress, including speaker Mike Johnson and other senior House lawmakers, called on Biden to resign immediately. Notably, Mitch McConnell, the GOP’s Senate minority leader, did not.

More to come.