WP said that the incident illustrates "frustration" within NATO with the pressure tactics used by Zelenskyy, as even some of his biggest supporters questioned "whether he was serving Ukraine's interests with his outburst."
WP's sources said ambassadors, ministers and other senior officials held informal talks on how the Alliance should respond.
U.S. officials raised the possibility of revising or removing the section to which Zelenskyy so strongly objected: "We will be in a position to extend an invitation to Ukraine to join the Alliance when Allies agree and conditions are met."
A U.S. official familiar with the conversations acknowledged that changes to the declaration were considered, saying that the administration of U.S. President Joe Biden was listening to Zelenskyy's concerns and hoped they could somehow address them.
However, three other senior politicians, two of whom were directly involved in the negotiations, said they strongly believe that Washington was prepared to water down the wording of the document to make it less welcoming to Ukraine's rapid accession to the Alliance.
"Some wanted to withdraw the reference to 'invitation' or find another place to put that word," said one senior NATO diplomat who participated in the talks.
Another top NATO diplomat said that while "several people" supported removing the phrase that upset Zelenskyy, the U.S. delegation "did not specifically want to take that promise" of invitation out of the declaration.
According to the newspaper, despite the incident, many NATO member states remain appreciative of Zelenskyy's demands and are maximizing their military efforts. Although many officials expressed irritation over the president's tweet, they appreciated that "the leader of an embattled nation must demonstrate he will do anything to extract the maximum on behalf of his people."
In the end, the United States and its allies agreed that they would retain the wording of the declaration that was presented at the Vilnius summit.
The document does not include a timeline for Ukraine's accession to the bloc, but is the result of efforts to persuade the Biden administration and European leaders to provide Kyiv with more concrete proposals amid Russian aggression.
On the second day of the summit, July 12, the head of the President’s Office, Andriy Yermak, also held an "intense conversation" with U.S. National Security Advisor Jake Sullivan during the first meeting of the NATO-Ukraine Council.
According to one witness to the conversation, Yermak tried to argue with Sullivan, who "looked determined," and their talks lasted about 30 minutes.
The source noted that the Ukrainian side's strenuous attempts to hold the line have exhausted and irritated some of Kyiv's staunchest supporters.
"It was not fun," one senior NATO official commented.
On July 11, Zelenskyy tweeted that NATO states were discussing the wording of the invitation to Ukraine to join the Alliance without Kyiv's participation.
He argued that "there was no readiness" to invite Ukraine to NATO or make it a member of the Alliance, so "a window of opportunity is being left to bargain Ukraine's membership in NATO in negotiations with Russia."
NATO Summit in Vilnius - what is the outcome for Ukraine?
On July 11-12, a NATO summit was held in Vilnius, attended by the leaders of 31 member states, including U.S. President Joe Biden, and additionally by delegations from Japan, South Korea, New Zealand, Australia, Ukraine, and Sweden (Turkey agreed to unblock its accession to the Alliance earlier). President Volodymyr Zelenskyy personally attended the summit.
Ukraine hoped to receive a clear signal of readiness to be admitted to the Alliance at the summit. Earlier, Foreign Minister Dmytro Kuleba stated that the allies had agreed that Ukraine would join NATO in the future without the MAP.
On July 11, in a joint communiqué, NATO countries announced that they would invite Ukraine to join the Alliance when member states agree and all conditions are met.
NATO Secretary General Jens Stoltenberg said that Ukraine does not need to fulfill the MAP anymore, and thus the path to NATO has been reduced from "two steps" to "one."
On July 12, Zelenskyy stated that he was convinced that Ukraine would receive an invitation to join NATO after the war.