There are many Marxists who look at the US/NATO war against Russia without historical materialism. They condemn Russia and the war in Ukraine as an "inter-imperialist war" between Russia and the US, but this is wrong mainly because they ignore the historical aggression movement of the "traditional" imperialist countries.
One such movement was the expansion of NATO, where the EU and the US were funding NATO and EU membership campaigns, especially in former socialist republics. They took advantage of nascent states and low institutional complexity to spread propaganda in these countries, initially through television and today through the Internet. They manipulate the public opinion of an entire nation, just to serve their interests.
And worse, NATO demands from these countries "political reforms" in order to enter NATO, which eventually resulted in extreme right-wing governments in these countries.
NATO has been expanding eastward into Russia, settling in the Czech Republic, Hungary, Poland, then Estonia, Latvia, Romania, and Bulgaria, with Estonia and Latvia bordering Russia. Furthermore, NATO has already stated if I'm not mistaken since 2008 that it intended to host Ukraine and Georgia, and not only that, it has frequently held military exercises with these countries. Both Ukraine and Georgia border Russia, Ukraine being the country that has the longest border with Russia.
In Ukraine, a government has been in place since 2014 that has openly advocated neo-Nazism and incorporated Nazi militias into its army. It promoted the persecution of ethnic Russians within the country and for 8 years the Ukrainian army assaulted the population of Donetsk and Luhansk provinces. School children were taught to hate Russians with children's stories portraying the Russian nation and its people as barbarians, monsters, as every government does with its enemies.
And now, with the Russian invasion, Finland, which also has a long border with Russia, has joined NATO. We already know what the historical trend of this will be. In addition, NATO has an indirect presence in Asia, mainly in South Korea and Japan, due to the presence of US troops in these countries (more than 80,000 soldiers in all).
It is very clear that NATO has been expanding toward Russia since the late 1990s, setting up governments hostile to Russians in its member countries for the sole purpose of generating a conflict with the country. In this way, it becomes possible to fragment the whole of Russia, to facilitate the plundering of that country's natural and human resources, and especially to prevent a competitive country from outgrowing the USA.
The idea that Russian aggression is part of an "inter-imperialist" conflict attempts to equate the US with Russia, as if both countries are waging war for similar reasons, or as if both are in the same position. The US/NATO has been hostile to Russia for decades, it's decades of constant aggression. To any Russian, who has seen it up close all these years, the war was a surprise, but everyone knew it was inevitable.
Marxists who defend the thesis of "inter-imperialist war" to condemn Russia and the US on the same "level" ignore all this historical development, and on top of that they use the argument that in Russia there is a right-wing conservative party in power. Or worse, they say that Russia is a bourgeois state and therefore does not deserve support.
It is true. In many aspects the Russian government is anti-communist, even. But all over the world we have bourgeois dictatorships or conservative governments. To take only this criteria of support would result in condemning the "inter-imperialist" war between the U.S. and Iraq, equating aggressors and aggressed. Because both are bourgeois dictatorships, therefore they do not deserve special consideration.
In the case of the war in Ukraine the "aggressor-aggrieved" relation is more subtle, because in the immediate appearance Russia invaded Ukraine. The aggressor-aggrieved relationship is between Russia-Ukraine, right? That seems to be the view of our Marxists, apparently. Losing sight of the background of NATO's actions, this war becomes a meaningless thing, as if Russia is wanting to take Ukraine for itself, to export its capital and control Ukraine's markets. It is a very similar discourse to the one NATO reproduces, of the invader Russia.
So who does the "imperialist Russia" discourse serve? Exactly the NATO side. Exactly the usual imperialists, which we are sick of knowing, the imperialists of the North Atlantic, the US and Europe. This discourse is aimed at undermining support for Russia in other nations, and gradually manufacturing a consensus that justifies a war against Russia.
The two sides of the war are not equal, and they do not wage war for equal reasons. Russia is a bourgeois dictatorship, as in much of the world, but it is part of a positive movement regarding the world market, an alternative movement to the US hegemony that for decades has plagued the countries of the world with its political and economic interference. Russia's partnership with China also adds strength to this alternative movement to the US-dominated institutions, the domination of the dollar, and the arbitrary interference in other countries.
Not at all, Lenin is so important complement to Marxism that you cannot ignore him.
Lenin's contributions include the understanding of imperialism, a more systematic approach towards understanding national liberation movements, his contributions to revolutionary praxis, the theory and practice of the dictatorship of the proletariat, many contributions of political tactics and strategy, tactics of revolutionary organization, his philosophy of organization (democratic centralism), his contributions towards a systematic dialectical materialist understanding...
Lenin's contributions far exceed any other Marxist in terms of revolutionary praxis. So Marxism is the philosophical worldview which instructs our understanding of the capitalist system, while Leninism is the body of work detailing strategy and tactics towards revolutionary action. So yes, Marxism-Leninism is an appropriate description of the current state of Marxist development.