Russia has massed a lot of troops on the Ukrainian border, especially near areas already semi-controlled by pro-Russian separatists who worked with Russian regulars to take those areas in 2014/15. This buildup is very large, in 2014 Russia used about 30,000 soldiers to support separatists and annex Crimea (along with a large number of defections from the Ukrainian Navy), but today they have about 130,000 troops on the border and are adding more every day. The Ukrainian army has also grown since 2014 but at best they can match the current Russian buildup man-for-man (they probably can't call up that many troops in reality), and even then the Russians have much more equipment, and that equipment is usually superior.
In 2014 the US imposed harsh sanctions on Russia to punish them for annexing Crimea, and although the sanctions hurt Russia was able to recover somewhat and their economy has been able to grow even with the sanctions still enforced, so many people believe that more sanctions basically aren't possible or in any case won't have nearly the effect on Russia that the previous sanctions did.
It's hard to know exactly what Putin wants or what he will end up actually doing, but these are the things I take note of:
Russia has had a hard time supplying their new territory of Crimea with electricity and water since sealing off the land connection with Ukraine. It would help them a lot if they had a direct land connection from Russia to Crimea (the have a bridge right now but it's not very big).
The separatists gained a lot of ground in 2014/15 with the help of the Russians, but since the Russian soldiers largely withdrew, they have been losing ground against a Ukrainian army that is no longer caught completely off-guard and has been building it's strength. If Russia wants to eventually annex these territories too, they need the situation to be more stable and under control, and the separatists probably can't do that without the help of Russian soldiers.
The new Ukrainian government is way more pro-US and pro-NATO than the old one, and Ukraine seems to be leaning towards NATO membership (although the going has been slow so far). If Russia feels that a NATO Ukraine is imminent, then they may also feel that they have only a small window of time to take new territory before NATO membership would make this too risky.
The last time Russia put troops into Ukraine and annexed their territory (Crimea), the western world got very angry but in the end didn't really do anything major. Putin may feel that the western powers basically don't have the nerve to actually stop him from operating in eastern Europe.
If Russia does decide to invade, it's likely that the Ukrainian army will not be able to effectively resist them. Economic sanctions are unlikely to deter Putin, as Russia has a good relationship with China, as well as being a key natural gas supplier for Europe (especially Germany, who plans to replace all their nuclear reactors with natural gas in the next few years). Military aid that makes Ukraine a larger threat to Russia may be counterproductive, as it may provoke Russia to act sooner to deal with the threat preemptively.
Russia has massed a lot of troops on the Ukrainian border, especially near areas already semi-controlled by pro-Russian separatists who worked with Russian regulars to take those areas in 2014/15. This buildup is very large, in 2014 Russia used about 30,000 soldiers to support separatists and annex Crimea (along with a large number of defections from the Ukrainian Navy), but today they have about 130,000 troops on the border and are adding more every day. The Ukrainian army has also grown since 2014 but at best they can match the current Russian buildup man-for-man (they probably can't call up that many troops in reality), and even then the Russians have much more equipment, and that equipment is usually superior.
In 2014 the US imposed harsh sanctions on Russia to punish them for annexing Crimea, and although the sanctions hurt Russia was able to recover somewhat and their economy has been able to grow even with the sanctions still enforced, so many people believe that more sanctions basically aren't possible or in any case won't have nearly the effect on Russia that the previous sanctions did.
It's hard to know exactly what Putin wants or what he will end up actually doing, but these are the things I take note of:
Russia has had a hard time supplying their new territory of Crimea with electricity and water since sealing off the land connection with Ukraine. It would help them a lot if they had a direct land connection from Russia to Crimea (the have a bridge right now but it's not very big).
The separatists gained a lot of ground in 2014/15 with the help of the Russians, but since the Russian soldiers largely withdrew, they have been losing ground against a Ukrainian army that is no longer caught completely off-guard and has been building it's strength. If Russia wants to eventually annex these territories too, they need the situation to be more stable and under control, and the separatists probably can't do that without the help of Russian soldiers.
The new Ukrainian government is way more pro-US and pro-NATO than the old one, and Ukraine seems to be leaning towards NATO membership (although the going has been slow so far). If Russia feels that a NATO Ukraine is imminent, then they may also feel that they have only a small window of time to take new territory before NATO membership would make this too risky.
The last time Russia put troops into Ukraine and annexed their territory (Crimea), the western world got very angry but in the end didn't really do anything major. Putin may feel that the western powers basically don't have the nerve to actually stop him from operating in eastern Europe.
If Russia does decide to invade, it's likely that the Ukrainian army will not be able to effectively resist them. Economic sanctions are unlikely to deter Putin, as Russia has a good relationship with China, as well as being a key natural gas supplier for Europe (especially Germany, who plans to replace all their nuclear reactors with natural gas in the next few years). Military aid that makes Ukraine a larger threat to Russia may be counterproductive, as it may provoke Russia to act sooner to deal with the threat preemptively.
*screams