If you're a Ukrainian, the world looks rather strange these days. Just a few weeks ago, the United Kingdom voted to give up its membership in the European Union, a privilege that Ukrainians have fought and died to try to gain. That decision now raises for reform-minded Ukrainians the unhappy possibility that a weakened and divided EU will no longer be there to push democratic progress forward.

Ukraine is not alone. In the 25 years since the disintegration of the Soviet Union and Soviet Bloc, the European Union has been a mighty force driving political and economic reform in many of these newly independent countries.

The carrot of EU membership — as well as funding and expert assistance from EU countries — helped countries like Poland, Slovakia, and Estonia undertake badly needed economic and political reforms. Moreover, EU investment and economic redistribution has helped produce positive economic growth and prosperity in many of its poorer member states.

Now, however, the Brexit vote has raised the very real possibility that Europe will increasingly turn inward and, as it focuses on its own problems, lose interest in further expansion and assisting those countries that have come to rely on its help, influence, and example. This is decidedly bad news for the EU’s newer and still-developing members, as well as for those nations that aspire to EU membership.

The EU has been a major force for political reform

In order to join the European Union, or to be considered for membership, candidate nations must meet certain standards and benchmarks. According to the European Commission:

Countries wishing to join need to have: stable institutions guaranteeing democracy, the rule of law, human rights and respect for and protection of minorities; a functioning market economy and the capacity to cope with competition and market forces in the EU; the ability to take on and implement effectively the obligations of membership, including adherence to the aims of political, economic and monetary union.

While Americans may take for granted that they have "stable institutions" and "a functioning market economy," creating such things from scratch is a complex and difficult job. That task is compounded when your country has been under the thumb of autocratic and corrupt dictators for generations and entrenched interests work actively against reforms.

It is in large part thanks to the demands of European Union membership that newer members like Bulgaria and Romania have been willing to take steps to root out the corruption that has long been endemic in their societies, reform their police and judicial systems, and open up their markets.

And the prospect of EU membership continues to drive politics in many countries that have not yet joined the bloc. For instance, right after the Brexit vote, Ukrainian President Petro Poroshenko wrote that "Europe’s real strength is its ability to inspire change in others" and described the EU as "the only path to a better future and the only remedy for the disease of egoism and division that has cost our Continent millions of lives."

In the Balkans, where Albania, Macedonia, Montenegro, and Serbia are all at various stages of trying to accede to the European Union — and Kosovo and Bosnia and Herzegovina are considered "potential candidates" — there is a lot of fear that Brexit will slow or stymie their chances to join. While current members of the EU have spoken about the need for the remaining 27 countries to unite, nations that sit outside the bloc worry that unity will mean a strict focus on internal matters.

The status of their young democracies is also a concern. Bosnian political analyst Adnan Huskić has raised concerns that in a situation where the United States in increasingly uninterested in the region and Europe has turned inward, "Russia, Turkey and other countries might step in, countries that do not contribute to the general security and the creation of environment that would support the development of democracy in [Bosnia and Herzegovina]."

Poland, which is often considered the poster child for the European Union’s success in encouraging political and economic reform, is understandably sad to see the United Kingdom leave. In many instances, Poland has acted as a kind of advocate for other Eastern European nations that have European aspirations, and Britain has backed them up.

Since the Polish government was exiled to London in 1939 as a result of the German/Soviet invasion, Poland and Britain have had a friendly relationship. And as the two largest EU member states that do not use the euro as currency, they have maintained that connection. It is no wonder, then, that the leader of Poland’s ruling Law and Justice party has called for "efforts aimed at making Britain return, including a second referendum."

The EU has brought economic growth and prosperity to poorer countries

Eastern European countries are concerned about the negative effects that Brexit may have on their economies, too. The newer, poorer nations of Eastern Europe have benefited greatly from EU-sponsored infrastructure projects and redistribution of the funds that each EU nation contributes to the general pot each year.

As one of the richer nations in the EU, the United Kingdom’s contribution has been around 8 percent of the EU’s total revenue. That chunk of money will either have to be made up by other nations or disappear altogether, lessening EU investment in Eastern Europe.

Croatia, the newest EU member, has worried aloud that Brexit may stymie the EU’s expansion into the Balkans, a step it sees as key for building economic growth in the region.

While Croatia itself has very little trade with Britain and does not expect to be very much affected by Brexit or the fall the British pound has taken since the vote results were announced, many of its neighbors are not in such a secure position. The World Bank lists the UK as the second most common destination for Polish exports, or 6.4 percent of all Polish exports. The UK is the fourth most popular destination for goods exported from the Czech Republic.

If workers in the UK begin to return home — either because they are forced to by new UK immigration laws or because conditions in the UK make it a less attractive place for immigrants to live and work, Eastern European countries could also see the high amount of remittances sent back to their countries drop sharply.

Those remittances — and the economic support they provide to their home nations — have been made possible by the EU’s rules on the free movement of people and labor, and has seen citizens of poorer countries like Poland move to much richer nations like the UK to find work. Poland alone has around 790,000 of its nationals living in the UK.

While the Economist Intelligence Unit does expect Brexit will mean "a drag on export growth in central Europe," the effects are not expected to be felt immediately. The United Kingdom is expected to formally apply for its divorce from the European Union in the next few months, an action that will begin a two-year process of conscious uncoupling. The conversations and negotiations done during that period will help determine how the nations of Eastern Europe will emerge on the other side.

Hannah Thoburn is a research fellow at the Hudson Institute focusing on Eastern European politics. She tweets on the former Soviet space @HannahThoburn.