Donald Trump has announced plans for “merit-based” legal immigration – but before the US president even stepped up to the lectern in the White House Rose Garden on Thursday afternoon, opponents declared the sweeping reforms “dead on arrival”.

Trump appeared to acknowledge as much when he warned that Democrats, who control the House of Representatives, might block the changes – a sign of his political impotence as the next presidential election draws ever closer.

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“If for some reason, possibly political, we can’t get the Democrats to approve this merit-based, high-security plan,” he said, “then we will get it approved immediately after the election when we take back the House, keep the Senate and, of course, hold the presidency.”

An audience of cabinet members, House and Senate Republicans and Trump’s senior adviser and son-in-law, Jared Kushner, primary architect of the immigration plan, rose to their feet to applaud.

But in a 25-minute address, in late spring sunshine, Trump made no mention of the Deferred Action for Childhood Arrivals policy, or Daca, that protects hundreds of thousands of undocumented immigrants brought to the country unlawfully as children. Safeguarding these “Dreamers”, after Trump threw their status into doubt in 2017, is a key priority for Democrats.

The president hit familiar notes about drugs, gangs and human smugglers crossing the US-Mexico border, touted his signature wall and infrastructure upgrades at ports of entry and promised to crack down on “frivolous” asylum claims. But he dwelled less on gory details than at similar set pieces in the past. Instead his emphasis this time was on legal immigration, which he claimed has not undergone a major legislative overhaul for 54 years.

Trump, who has a long history of using foreign and undocumented labour at his own hotels and resorts, called his plan “pro-American, pro-immigrant and pro-worker”. He declared his intent to transform the nation’s “green card” system so that it would favour people with high-level skills, degrees and job offers instead of relatives of those already in the country.

Trump noted that the US admits 1.1 million immigrants as permanent legal residents each year. Green card holders get lifetime authorisation to live and work in the US and a five-year path to American citizenship. “This is the most prized citizenship anywhere in the world by far,” he said.

Facebook Twitter Pinterest Trump’s senior adviser and son-in-law, Jared Kushner, is a primary architect of the immigration plan. Photograph: REX/Shutterstock

Currently two in three legal immigrants come to the US on the basis of random chance, the president continued, because they have a relative in the US, “and it doesn’t really matter who that relative is”. Another 21% gain admission either by random lottery or because they are selected for humanitarian relief.

“Random selection is contrary to American values and blocks out many qualified potential immigrants from around the world who have much to contribute,” Trump insisted. “While countless, and you wouldn’t believe how many countries, like Canada, create a clear path for top talent, America does not.

“Under the senseless rules of the current system, we’re not able to give preference to a doctor, a researcher, a student who graduated number one from the finest colleges in the world, anybody. We’re not able to take care of it. We’re not able to make those incredible breakthroughs.”

The president added: “If somebody graduates top of their class from the best college, ‘Sorry, go back to your country.’ We want to keep them here. Companies are moving offices to other countries because our immigration rules prevent them from retaining highly skilled and even, if I might, totally brilliant people. We discriminate against genius … we won’t any more once we get this passed.”

Under the new plan, 57% of green cards would be awarded on merit as opposed to the current 12%. Immigrants would be expected to be financially self-sufficient, learn English and pass a civics exam. The diversity visa lottery, which offers green cards to citizens of countries with historically low rates of immigration to the US, would be terminated.

“If adopted, our plan will transform America’s immigration system into the pride of our nation and the envy of the modern world,” Trump added.

Attempts to improve the immigration system have gone nowhere for three decades amid deep partisan divisions. A compromise plan last year, that would have helped Dreamers and added money for border security, collapsed in acrimony.

Thursday’s effort has little chance of advancing through Congress before the 2020 presidential election. Even some Republicans have expressed reservations, noting that it does not reduce overall rates of immigration. “The White House plan makes no change to the number of green cards allocated each year,” Trump had said.

Democrats were more aggressive in their condemnation. The House speaker, Nancy Pelosi, said: “This dead-on-arrival plan is not a remotely serious proposal. The White House has repackaged the worst of its past failed immigration plans … To say that this plan’s application criteria are ‘merit-based’ is the height of condescension.”

Before Trump’s announcement, the Senate minority leader, Chuck Schumer, said: ﻿“When Stephen Miller, one of the president’s most virulently anti-immigrant advisers, is in the room crafting your immigration plan, it’s a surefire failure.”

And Pili Tobar, the deputy director of America’s Voice, a group that advocates for immigrants’ rights, warned: “This is not designed to be a serious policy proposal – it’s a message document that’s a misguided attempt at political posturing. To say it’s dead on arrival would be generous.”