What would happen if Ukraine joined NATO?

STORY: What would happen if Ukraine joined NATO?

After Russia invaded last year, Ukraine stepped up its efforts to join NATO.

[Volodymyr Zelenskiy, Ukrainian President]

"We shall be free, strong and of course in NATO."

Ukraine argues that the security assurances given by Moscow, Washington and London when it relinquished its nuclear arsenal to Russia in 1994 were clearly worthless.

While eastern European countries say some sort of a road map should be offered to Kyiv, the U.S. and Germany are wary of any move that might take the alliance closer to war with Russia.

Russian President Putin has cited NATO's expansion towards Russia's borders over the past two decades as a key reason for his decision to invade Ukraine.

[Vladimir Putin, Russian President]

"NATO, of course, is being drawn into the war in Ukraine."

So what steps need to be taken?

Any expansion of the North Atlantic Treaty Organization must be agreed by all 31 members.

In 2008, NATO leaders agreed that Ukraine - a former Soviet state – could eventually join the alliance.

But they did not give Kyiv a so-called Membership Action Plan - or MAP.

This was U.S. President George Bush in 2008:

"I strongly believe Ukraine and Georgia should be given MAP, and there's no trade-offs, period."

Under the MAP process, candidates have to prove they meet political, economic and military criteria and are able to contribute militarily to NATO operations.

Since 1999, most countries - including former communist ones - aiming to join NATO have participated in a MAP, although this procedure is not mandatory.

Finland and Sweden, formerly neutral states which worked closely with NATO, were invited to join the alliance directly.

It's unclear what Ukraine's path to membership will look like as more and more countries - including Britain and Germany - suggest skipping the MAP process.

This is U.S. National Security Advisor Jake Sullivan:

“That is an active discussion among allies right now, whether Ukraine has in fact moved beyond the need for MAP."

Ukraine's military has taken major steps towards NATO standards since Russia's all-out invasion.

The process is accelerating as its Soviet-built arms and ammunition gradually run out and the West trains Ukrainian troops according to NATO standards and sends more and more advanced weaponry.

British Foreign Secretary James Cleverly:

"They are now very experienced in the utilization of NATO standard equipment, NATO doctrine and NATO tactics. So however long it might otherwise have taken Ukraine to join NATO, their actions will inevitably have shortened that time scale."

So why is Ukrainian membership so sensitive?

A mutual assistance clause lies at the heart of the NATO alliance.

It’s cited as one of the main reasons why Ukraine cannot join NATO while in conflict with Russia, as this might immediately draw the alliance into an active war.

The Kremlin portrays the expansion as evidence of Western hostility to Russia.

Western powers deny this, saying the alliance is wholly defensive in nature.

Moscow has said it would cause problems for many years to come if Ukraine joined NATO and has warned of an unspecified response to ensure its security.

EUROPEAN UNION / Ria Novosti / Chatham House / Reuters / Concord Press Service / RUSSIAN POOL / NATO TV / 35th Separate Brigade of Marines via Facebook / 68th Separate Hunting Brigade 'Oleksy Dovbusha' / Ostorozhno Novosti / UK Pool