TL;DR - not at all.

Let's look at Poland's eastern borders.

During the interwar period, Poland underwent a spontaneous and ludicrously successful invasion of the Soviet Union. This arose from the Polish-Soviet War, where after being driven all the way to Warsaw and Lwow, Poland routed Russian forces and drove them back into Russia in an event known today as the Battle of Warsaw or the 'Miracle on the Vistula'. In the aftermath, though, they executed a military invasion of what is now Belarus, Ukraine, and Lithuania - generating animosity from these ethnic groups in the process. Poland ended up annexing sizable Ukrainian, Belarusian, and Lithuanian territories; not enough to become a truly multinational empire like the Polish-Lithuanian Commonwealth or even the Soviet Union, but just enough for them to be rather frank about how much they hated their overlords and wanted to be with others of their nationality. The three aforementioned communities were split in two by interwar Poland, which ended up being an acceptable solution for nobody - Soviet, Polish, or otherwise.

No Ukrainian, Belarusian, or Lithuanian governments would even think of supporting a federation with the Polish government - if they even existed, that is. In both Poland and the Soviet Union, Ukrainians and Belarusians were persecuted by both their respective governments and the Poles/Russians they bordered. Lithuania remained an independent nation, but Vilnius/Wilno - the cultural and political capital of Lithuania, as well as its largest city - had been annexed by Poland after the Polish-Soviet War, causing much distrust from the Lithuanian government.

All of this is in addition to political strife in Poland, where multiple coups and abdications took place during the interwar period and not a single presidential term was successfully completed. The idea of submitting to such a government was not the brightest in the eyes of any country.

Sources:

• Neal Ascherson - The Struggles for Poland

• Norman Davies - White Eagle, Red Star

• Norman Davies - God's Playground: A History of Poland (Volume II)