The State Department said the visit to Luxembourg was cancelled so Pompeo could attend transition meetings with President-elect Joe Biden’s foreign policy team but, according to Reuters, the decision was made after European Union and Luxembourg officials refused to meet with the American secretary of state.

Reuters cited American and European diplomats in its report, describing the development as an “extraordinary snub.” Pompeo had planned to meet with Luxembourg’s foreign minister Jean Asselborn before heading to Brussels to meet with EU and NATO leaders.

The Luxembourg visit was cancelled first because of the reluctance of politicians there to meet with Pompeo following the storming of the Capitol by a Trump-supporting mob, Reuters reported. Asselborn branded Trump a “criminal” and “political pyromaniac” in a radio interview the day after the violence, which left five people dead.

The trip to Brussels was cancelled at the last minute, according to Reuters. The itinerary of the visit raised eyebrows given Pompeo had no scheduled meetings with EU officials or any events at the NATO headquarters in the city. A diplomatic source told Reuters that allies were “embarrassed” by Pompeo.

On Wednesday, Pompeo was due to have a private dinner with NATO Secretary-General Jens Stoltenberg and meet with Belgian Foreign Minister Sophie Wilmes, Reuters said.

Before the visit was cancelled, Pompeo wrote on Twitter that he was “looking forward” to travelling to Brussels “to reaffirm the deep and enduring partnership between the U.S. and Belgium.”

Pompeo has been tweeting what he considers the administration’s major successes since January 1, seeking to define the legacy of Trump’s foreign policy. Pompeo is one of the president’s staunchest allies and has been widely criticized for politicizing the State Department.

Trump’s “America First” instincts have prompted much concern at home and abroad. Critics have claimed that the president, Pompeo and others have eroded American leadership and undermined the long-held alliances underpinning the U.S.-dominated international order.

Pompeo has argued that the administration broke with diplomatic conventions to achieve new successes, whether in confronting American rivals or building alliances.

The secretary of state has lauded the “swagger” of the Trump administration, which helped secure the Abraham Accords normalization deals between Israel, the United Arab Emirates, Bahrain, Sudan and Morocco.

The administration also drew closer with India and Taiwan as New Delhi and Taipei both considered how best to contain China, with the White House leading the global effort to push back on Beijing’s authoritarianism.

Pompeo celebrated the administration’s success in building on American alliances. “My StateDept team did more than any other to build alliances that secured American interests,” he wrote in one tweet, adding: “#EffectiveMultilateralism makes America safer.”

In another, he wrote: “America First doesn’t mean America alone. The Trump Administration has pushed groundbreaking reforms at multilateral institutions and forged alliances to meet the threats of our time.”

The former Kansas congressman and CIA chief is expected to use his administration experience to run for office in future, whether in the Senate or for the presidency. Pompeo’s tweet campaign and global farewell tours appear to be laying the groundwork for such a bid.

Pompeo is likely to retain his opposition to “globalism” in any future run, as well as his commitment to the nationalistic, unilateral foreign policy outlook that Biden claims has left America’s international reputation “in tatters.”

In one of this month’s tweets, Pompeo said: “Treaties, like alliances, can outlast their sell-by-date. Always have to keep evaluating their usefulness.”

In another, he wrote: “The Trump administration led the world in reforming multilateral institutions and ditching bad deals,” referring to Trump’s withdrawal from the Paris climate accords, the Joint Comprehensive Plan of Action nuclear deal with Iran, and arms control treaties with Russia and others.

The administration has been particularly dismissive of United Nations bodies and has accused some—including the World Health Organization—of surrendering their independence to China. Trump’s decision to withdraw U.S. funding from the WHO in the midst of the coronavirus pandemic was criticized by a swathe of world leaders.

In another tweet, Pompeo said: “America is a generous country, but prior administrations let the UN treat us like a piggybank. UN was inefficient, wasteful and manipulated by malign actors. It needed to shape up. Fast.”

Pompeo defended Trump’s decision to withdraw from the WHO, the UN agency supporting Palestinian refugees and UNESCO in one post. “If we can’t fix it, we won’t keep wasting time or US taxpayer money,” he said. “Our good faith efforts to reform @WHO,@UNESCO, @UNRWA and other corrupt organizations were rejected, so we left & found better ways to put #AmericaFirst. #CommonSense”

Pompeo and Trump have also pushed back against the International Criminal Court, even sanctioning prosecutors for investigating alleged war crimes by American soldiers in Afghanistan. “Globalism is dangerous and tramples our sovereignty,” Pompeo wrote in one of several tweets condemning the court.