A White House boycott by Sinn Fein, the SDLP and Alliance was irrelevant and ineffective, the DUP leader has claimed.
Gavin Robinson said it was revealing that Donald Trump was unaware of their absence as he welcomed his “new friends from Northern Ireland” this week.
Political leaders made the traditional trip to the US this week ahead of St Patrick’s Day.
First Minister Michelle O’Neill travelled to Carolina for a business event but returned home rather than attend the Washington events as part of Sinn Fein’s protest against Mr Trump’s threat of mass expulsion of the Palestinian people from Gaza.
The SDLP and Alliance also stayed away.
Asked about the boycotts while meeting Irish premier Micheal Martin in the Oval Office, Mr Trump remarked: “I haven’t heard that, I really haven’t heard that.”
Deputy First Minister Emma Little-Pengelly and other senior DUP figures, including Communities Minister Gordon Lyons, did attend the Washington festivities.
Later, the president told a dinner: “I also want to thank my new friends from Northern Ireland for being here … it’s a great honour.”
Mr Robinson said the experience of Northern Ireland’s divided society shows that political relationships are necessary, even when strong disagreement exists.
“It was revealing that the self-imposed exile of Michelle O’Neill, Claire Hanna and Naomi Long wasn’t even on the President’s radar, yet he warmly welcomed his ‘new friends from Northern Ireland’ to the White House,” he said.
“That tells you everything you need to know about just how ineffective and irrelevant their boycott has been.”
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In his weekly email to DUP members, Mr Robinson said the trip helped “foster political relationships, develop economic opportunities, and enhance cultural links”.
He added: “You don’t have to agree with everything someone says or does to advocate for your people.
“If our own political arrangements have taught us anything, it’s that political relationships are often necessary, even when they’re not with whom we would choose.”
Mr Robinson said the deputy First Minster’s meeting with Mr Trump was “an important opportunity to put our priorities on the President’s radar”.
On the wider engagement in the US, he added: “A crucial part of these discussions was ensuring Northern Ireland remains protected from potential tariffs imposed on the EU and UK.
“We made it clear that the unacceptable arrangements under the Windsor Framework leave us vulnerable in a scenario where tariffs are imposed, and we pressed the case for Northern Ireland’s position to be properly recognised.”
Body language expert analysis of Micheál Martin meeting Trump in the White House
Mr Trump has threatened to slap tariffs on American imports as part of a deepening trade dispute between the US and the EU.
On Wednesday, he imposed 25% tariffs on steel and aluminium imports from around the world, a move hitting the EU hard, which in retaliation announced tariffs on €26bn (£20bn) of US goods beginning in April.
Post-Brexit trade arrangements for Northern Ireland mean that any US imports into the region will be treated the same as those entering the EU, and could become more expensive because of the new tariffs.
With the UK so far not imposing tit-for-tat levies on its US imports, it is feared Northern Ireland could end up a more expensive place than the rest of the UK to buy those goods.