The U.S. has the world's largest economy and broadest level of international security interests and responsibilities. As such it has taken the lead in response to the Russian invasion of Ukraine with military aid and punitive economic sanctions against Russia.
While economic sanctions have been used frequently, the conventional wisdom in international relations has been that they are ineffective in changing the behavior of target nations. The major weakness in the application of sanctions is lack of complete participation by significant governments which provide a "back door" for financial and trade transactions for the target. In the case of Russia these are significant. The non-participants include China and India, the world's two most populace nations. China has the second largest of the world's economies (GDP) and India is number six. Russia's economy is number eleven. Thus the current sanctions program, while being more comprehensive and severe than most in the past, has major loopholes which mitigate the effectiveness and can be expected to delay positive outcomes.
Another complicating factor in prosecuting the response to Russia's invasion is international context. The conflict is not occurring in a vacuum. Prior to the February, 2022 invasion, the world was neither at peace nor free from threats of higher levels of conflict and those issues remain. Several have ties to Russia which have to be taken into account as the Ukrainian situation plays out both militarily and diplomatically, including the post-conflict realities.
In Syria, the multi-party civil war which began in 2014 as part of the "Arab Spring" movement, is still going on. In the early years, a combination of mostly independent Sunni Muslim militias including the terrorist Islamic State and affiliates of Al Qaida, as well as allegedly more politically moderate forces fighting under the name "Syrian Democratic Forces (SDF), had the regime of dictator Bashar al Assad in a precarious situation.
Then Russian President Putin decided to intervene with aviation and special forces ground units. These groups coordinated with a similar intervention to support Assad's military by the Iranian client, the Shi'ite Hezbollah militia and quasi-political party which operates out of Lebanon. Iranian Revolutionary Guard Corps forces also showed up. Together these extra-national intervening elements along with the Syrian national army, turned the tide against the collection of anti-Assad forces. Over the next several months, the battle became increasing violent with large numbers of civilian deaths and millions of Syrians leaving the country to avoid the conflict. U.S. Special Forces and air elements also intervened against the Islamic State, and with bombing missions against Syrian air fields in response to Assad's air attacks on civilian populations; in effect fighting on both sides.
The Russian, Iranian client Hezbollah, and Iranian forces have complicated an already complex international problem in the volatile Middle East which because of Russian involvement, can be more complicated because of the Ukraine war and the requirements of any settlement of that conflict Russia may try to leverage it's negotiating positions to pursue its interests in both/
Iran represents a major security threat across the Middle East. It shares borders with Iraq, Afghanistan, Pakistan, a nuclear power, Turkey, a NATO member, and Saudi Arabia, owner of 17% of the world's oil reserves with recent production levels of 2.5 million barrels per day. Its theocratic Shi'ite government is openly hostile to the Sunni monarchy in Saudi Arabia and it seeks regional influence in Iraq, Syria, Lebanon, and Yemen, and is a sworn enemy of Israel, America's historic ally in the Middle East region.
Currently, President Biden has committed to renew the Joint Comprehensive Plan of Action commonly known as the "Iran nuclear deal", which was fostered by President Obama and then shut down by President Trump. The original agreement which was intended to restrict Iran's ability to develop nuclear weapons, was widely criticized for being to narrow, too weak to enforce adequately, as well as being time limited.
The agreement's members known as The Five + 1, include the U.S., UK, France, China, and Russia, all permanent members of the UN Security Council, and Germany as well as representatives of the European Union and Iran. Iran was brought to the negotiating table by the imposition of harsh economic sanctions and the blocking of Iran's international reserve currencies which were held outside of Iran.
The renewal negotiations are reportedly making progress and some say they are close to completion. There is a basic irony with respect to the negotiations because Russia is currently participating in the discussions in meetings with Iranian officials in Vienna, Austria. Two things make this situation problematic. One is the fact that Russia is an ally of Iran's military client Hezbollah in Syia, and thus an indirect ally of Iran. Another, is the fact that the failure of the agreement so far to include restrictions on Iran's ICBM development which would be the delivery system for nuclear weapons as well as a tool for significant conventional weapons aggression. Iran's sponsorship of international terrorism is also absent from the agreement.
Russia as a de facto ally of Iran, has a significant missile arsenal which it has demonstrated in its conflict with Ukraine and would be an attractive supplier of the technology or weapons if their restrictions were not included in the final agreement.
In fact the Russian emissary to the negotiations in March declared that as a member of the P5+1 negotiating team, when the sanctions against Iran are removed Iran would be free to engage in bilateral trade with Russia and not be in violation of the economic sanctions imposed on Russia in response to the invasion of Ukraine. If Iran chose to do so, especially in the areas of nuclear technology and military equipment, there is little that Biden could do about it. After promising to renew the agreement that Trump canceled and spending months in negotiation, he needs a foreign policy "victory' to help his struggling approval polls in advance of the November, 2022 mid-term elections and he is unlikely to upend the new agreement if and when the other members of the 5+1 see it as completed.
One of the most intractable and enduring conflicts currently underway is the civil war in Yemen. Yemen is a large but narrow country stretching along the southern border of the Arabian peninsula abutting the Arabian Sea on the south and the Red Sea on the east. It is a poor nation of @30.4 million people which finds itself in 7 year internal conflict enabled by outside nations because of its location and regional geopolitics.
What began as an ethno-religious uprising against an authoritarian leader impacted the interests of Saudi Arabia which shares a southern border with Yemen and Iran which shares a maritime border with Saudi Arabia between the narrow 210 mile width of the Persian Gulf.
This is important because of Iran's regional efforts of political and military interference cited above and in most instances based on its Shi'a Muslim identity which it uses as wedge to gain influence into politically unstable states with Shi'a populations. Iran thus became a logistic and political supporter of the Shi'a Houthi forces attempting to over throw the Sunni government of Yemen. Iran has long been a hostile rival of Saudi Arabia, both because of its oil wealth and political importance, its moderate stance to the West and its harsh treatment of its own Shi'a minority.
Saudi Arabia, fearing Yemen would become a hostile client state of Iran's if the Houthis prevailed, put together a coalition of Sunni Arab states to launch a military intervention in Yemen against the Houthis in 2015 which continues to this day.
Russia has a clear relationship with Iran which reflects both a desire to be a power player in the Middle East and a mutual supporting anti-West attitude. To this end Russia has tried to play the role of mediator in the Yemen conflict including outreach to Saudi Arabia.
Saudi Arabia has leaned towards the West, especially the U.S. where it buys most of its military equipment. In most recent administrations the U.S. has recognized that the Kingdom is a theocratic and authoritarian state but its importance in the region as both a major supplier of oil and as a barrier to Iran's expansion of influence has resulted in give and take moderation in their relationship. However, President Biden's recent public accusation of de facto head of government Prince Mohammed bin Salman as a "murderer" for his alleged role in the assassination of anti-monarchy Saudi journalist Jamal Kashoggi, has soured the relationship, as has his plans to restart the "Iran nuclear deal" which includes lifting the economic sanctions on Iran, but so far does not include prohibitions on international terrorism and ballistic missile production. The new hostilities on the part of bin Salman were obvious recently by the Saudi's refusal to talk to Biden about increasing oil production in the face of shortages in relation to the economic sanctions on Russia.
Russian diplomats appear to believe this offers an opportunity to increase influence with Saudi Arabia which means a bigger role to play in the Middle East region, all at the expense of the U.S.
China's support for Russia in the UN and its non-participation in the economic sanctions policies imposed on Russia is just part of a post-Soviet relationship which was emphasized in Putin's February, 2022 visit to Bejing just prior to the Russian invasion of Ukraine.
The United Nations is a mirror that reflects the international, political/economic alignments of it's 193 members and gives a voice to the majority who lack individual influence with the few world "powers". It's Charter outlines the hopeful promise of peaceful settlement of dispute
"... to save succeeding generations from the scourge of war, which twice in our lifetime has brought untold sorrow to mankind, and to reaffirm faith in fundamental human rights, in the dignity and worth of the human person, in the equal rights of men and women and of nations large and small, and to establish conditions under which justice and respect for the obligations arising from treaties and other sources of international law can be maintained. . ."
Despite its' noble goals and the hopes of many that the UN would play a role in defense of Ukraine and punishment of Russia, the realities of human nature, tribal like national animosities, ethnic, religious and dramatic resource differences, and the quest for power among national leaders, have produced continuous wars since the UN's founding in 1945. That is the context in which the world now faces the Russian/Ukraine war.
Unlike all previous wars since 1945 the conflict in Ukraine includes one of the world's "super powers" as an aggressor. Hopes for a united front by the world body's members which could influence the situation isolate or even intervene are thus not a possibility. Russia is one of the five permanent members of the Security Council which have veto power over any Security Council resolution which are required for security related interventions i.e. "peace keepers"; "peace makers", sanctions etc. The most punishing action the UN has been able to carry out against Russia is the General Assembly's decision to expel Russian from the 47 member UN Human Rights Council.
Russia's seat on the Security Council and indeed, it's membership in the UN is a Charter protected fact. Only a vote by the Security Council can change these facts and Russia, as a permanent member can use its' veto to protect it's status. An amendment to the Charter changing the procedures would also require a Security Council vote.
The General Assembly did approve a resolution in March condemning the invasion of Ukraine and demanding a full withdrawal of Russian forces. General Assembly resolutions however are just opinions without legal standing.
Even so, the difficulty of imposing resistance on Russia by the international community can be seen in this non-enforceable vote. While it passed with a huge majority, the shadow of Russia's power was felt by four members who voted against it; Belarus, North Korea, Eritrea, and Syria as well as Russia itself. But even more to the point, 35 nations chose not to condemn the invasion by abstaining. Most of these were African nations, many of whom have authoritarian leaders themselves but the key abstainers included China, India, Iran, Iraq, Pakistan and Viet Nam and in Latin America, El Salvador and Nicaragua.
Thus the reality is: the conflict in Ukraine will not be carried out in isolation of world wide international security issues and will endure for months; Putin seems confident that the people of Russia can endure the pain of cultural isolation and economic sanctions; Russia's influence in world affairs under Putin will remain a threat to Western interests no matter what the terms of the final resolution of the Ukraine conflict are.