(CNN) The UK has more or less made up its mind that the Russian state -- or at least a part of it -- was behind the use of Novichok in an attempt on former Russian spy Sergei Skripal's life in Salisbury last weekend.

If we are to accept Britain's "it could only be them" argument, based on the nature of the poison, then we must also ask some other questions -- chief among them, why would Russia do this in Britain, and why now?

First, Britain is currently weak on the world stage. While it is hard to admit this, virtually every relationship it has is in tatters.

Theresa May's government is reliant upon a small Northern Irish party, the Democratic Unionist Party, for its slim parliamentary majority. Every month or two, a leadership challenge is heard whispering in the wings.

May has been more or less invisible for the first week of this challenge. But the alternative isn't much better. The leader of the opposition, Labour's Jeremy Corbyn, suggested on Monday that dialogue with Russia was the best response to its alleged use of chemical weapons on British soil.

You can see the cracks in the British establishment's resolve from space. And this is before you consider the long-term animosity Russian hawks have against the UK: they lost the Cold War to the Americans, who they begrudgingly respect.

They still hate the British from the empirical squabbles of the 19th century. You could hear a little bit of that on Tuesday when Russian foreign minster Sergei Lavrov said "the era of colonialism is over".

Amid the wrangling of Brexit, this is not a time when the UK can count upon its European allies to make uncomfortable economic decisions -- like wide-ranging sanctions against Russia -- without question.

In fact, it simply amplifies the UK's greater need for European solidarity and cooperation.

And then there is the UK's so-called "Special Relationship" with the US, which looks slightly less special, ever since US President Donald Trump's visit to London keeps being kicked around, and since Downing Street had to chastise the US Commander in Chief for retweeting radical, right-wing, racist propaganda.

As with Europe, this isn't a time when London can unwaveringly count on US support. While speaking with reporters about the firing of Secretary of State Rex Tillerson, the President said that while he would take May's findings on the nerve agent "as fact;" the US would only respond when he is satisfied that they've got "the facts straight" and that he "agreed" with the British findings.

This really is the worst time in decades for the UK to need the help of its serious allies. Its leadership at home and on the world stage is weak, and the show of strength London must put on now will only work with the steel of solidarity from its allies.

Why would Moscow do this now?

The Russian presidential elections are days away, so logically rocking the boat now makes little sense, given that current President Vladimir Putin is assured victory, and his greatest challenger in most opinion polls is "undecided".

It could herald uncomfortable sanctions and further isolate Russia, which could possibly damage Putin's cherished victory margin.

Yet those who believe in-part of the Russian state's guilt in the Skripal affair would say that the polls don't really matter, but the message sent by Skripal's poisoning does.

It sends the message that Moscow is powerful, is unafraid to chase traitors anywhere, is able to thumb its nose at NATO members and former world powers, and is resilient to all possible consequences. That's perhaps a message designed to reassure hawks in Moscow that the next Putin term will not see a rapprochement with the West.

But there could be other dynamics at play. The Kremlin -- and the Russian elite of courtiers and oligarchs around it -- is not always united in one voice. You might say it at times makes the bloody and bitter satire the Death of Stalin look a bit like a documentary.

And the assured new Putin term is also -- under the current Russian rules, which limit more than two terms in succession -- his last. So oddly, before a ballot is even cast, a form of succession race is under way.

There will be hardliners jostling to position themselves as guarantors of Russian sovereignty and supremacy.

And if you accept that every shadowy move from Moscow may not have the explicit oversight of the Kremlin's head, a brazen attempt on a traitor's life galvanizes that reputation.

It forces the hand of Putin in this next term. And it lays the groundwork for either the kind of successor he must appoint, or bolsters the argument made in the past that without his strong hand in a time of crisis and confrontation, the country could collapse into bickering and chaos.

However you parse the last week, it does not look good for Britain or Russia. Putin described the collapse of the Soviet Union at the greatest geopolitical catastrophe of the last century, and somewhere in his heart the former KGB spy who saw the Berlin Wall fall must harbor a desire for some sort of revenge on NATO - to unpick the assurances of collective security.

Picking on its politically weakest power -- the UK -- at a time of crisis is one way of showing Russian resurgence.

But the erratic and reckless move shows perhaps that Moscow is itself undergoing a period of instability, in which this is designed to cement an ugly, future direction.