Ukraine is building its military back up from the nadir of 2014 which the pro-Russian government had allowed to deteriorate dramatically. In 2015 Ukraine's defense budget was $3.1 billion and the military had been expanded dramatically.
But given Russia's advantage, the state of the military is not the most important task Ukraine has to work on:
Indeed, it would be naive to believe that it is possible to modernize the Ukrainian military without reform in other spheres of Ukraine’s government. Military reform will only succeed if Ukraine finds ways to limit corruption, develop a more democratic political system, and respect civil rights, especially linguistic and cultural rights of national minorities. Ukraine’s military reform effort is ultimately not only a question of modernizing its equipment. Modernizing and improving the management of Ukraine’s military is ultimately a more important—if more challenging—determinant of the success of military reform.
As I've argued, if Ukraine is just a smaller version of corrupt Russia, Russia will win.
But if Ukraine truly combats corruption and achieves economic status of countries in the West, Ukraine can defeat Russia.
Remember, Ukraine has one threat to defeat: Russia. Russia has a far longer border with potential threats across a long border from the more powerful NATO in Europe, the rising China in Asia, the powerful Japanese and South Koreans, and America behind them. And there is potential unrest on their Central Asian border. This is simplistic but somewhat illustrative: Russia's land border is over 20,000 kilometers while Ukraine's is under 5,000.
Yet so far, Russia has far more money to spend on a military than Ukraine because Russia's GDP is more than 13 times Ukraine's GDP. Russia's GDP is above $1.5 trillion while Ukraine's is under $110 billion. But it is not hopeless when you consider America has a GDP nearly 13 times greater than Russia, and Russia poses a threat to America. Russia's threat to Ukraine is diluted by the far greater Russian security problems. And already, Russia cannot devote the power to occupy and pacify Ukraine.
And if Ukraine can get a GDP of Poland, which with only 38 million people has five times Ukraine's GDP and a GDP per capita greater than Russia, Ukraine could make itself too hard to defeat with what Russia can afford to devote to the Ukrainian border. Russia has 147 million people while Ukraine has 42 million people. With a Polish level, Russia's economic edge would shrink to a manageable level.
Will Ukraine find the Russian threat is bad enough to build rule of law as the foundation of Ukrainian military power? If not, they should get used to being The Ukraine again.
