Wladislaw used the title of the
King of Sweden, although he had no control over Sweden whatsoever and never set foot in that country. He would continue his attempts to regain the Swedish throne, with similar lack of results as his father.
In internal politics he attempted to strengthen the power of the monarchy, but this was mostly thwarted by the
szlachta, who valued their independence and
democratic powers. Wladyslaw suffered continuing difficulties caused by the efforts of the Polish
Sejm (
parliament) to check the King's power and limit his dynastic ambitions. The Szlachta viewed Vladislaus' military dreams as an attempt to strengthen his position during war and thus the
Sejm strongly opposed the majority of his plans for war (for example, with Sweden in
1635 or Turks in
1646), and usually thwarted them by denying the funds for military campaigns and withholding its cosignature on the
declaration of war. Similarly, Wladislaw's foreign ambitions came to little, as his attempts to mediate in the Thirty Year's War between the warring German and Scandinavian powers came to nothing, and his support for the Habsburgs brought him almost nothing in return.
In 1638 Władysław proposed that still not paid dowries of his mother and second wife of Zygmunt III would be protected by one of Silesian duchies (preferably opolsko-raciborskie). In 1642 proposed to give Habsburgs his rights to Swedish throne in exchange for giving him Silesia in deposit.
Ludovico Fantoni, sent to Vienna in summer 1644 proposed to exchange Wladysław's incomes from Bohemian estates in Treben for duches opolsko-raciborskie and cieszyńskie (of Cieszyn). At the beginning of 1645, tired by constant stalling of Vienna's court, Władysław said to Emperor's envoy sent to Warszawa,
Maximilian Dietrichstein, that Poland will cooperate with Sweden – it was an open threat (that he could take Silesia with Swedes help and against Emperor) pronounced by fact that on 6th of March 1645 Swedish general
Lennart Torstensson defeated Emperor's, Bavarian and Saxon forces in
battle of Jankov and started march against Vienna. Now Emperor was again ready for discussion and sent
Johannes Putz von Adlertum to Warsaw in April 1645 giving him wide prerogatives in transferring rights of duchy opolsko-raciborskie to son of Władysław and Cecylia Renata, Zygmunt Kazimierz as a hereditary fief. Negotiations eventually ended with Habsburgs success and Polish failure. Duchy was given not as a hereditary fief but 50 years long deposit and owner was required to swear allegiance to king of Bohemia (thus it could not be Polish king), but as an exempt Władysław would rule duchy until his son was an adult. Additionally Władysław promised to lend Emperor 1100000
złoty (minus still not paid three dowries).
Many historians argue that Wladislaus was very ambitious and dreamed of achieving great fame through conquests, and in the latter years he planned to use the Cossacks to provoke the Turks into attacking Poland so that his military leadership would be indispensable. On various times he set his sights on regaining the Swedish crown, capturing the Russian throne and even conquering the entire
Ottoman Empire. He was often able to convince the restless
Cossacks to join his side, but with little support from the
szlachta and foreign allies (like the
Habsburgs), he constantly failed in those attempts, often resulting in unnecessary border wars and diluting the strength of the Commonwealth, which later proved fatal when the country was finally invaded by its neighbours.
Some Polish historians claim that Wladislaus had short temper and when angered, could act to take revenge without considering all consequences. E.g. when Protestant szlachta blocked his plans for war with Sweden in 1635, he turned back to pro-Habsburg politics, sent them military help and married archduchess Cecylia Renata. Had many plans (dynastic, personal, about wars, territorial gains: regaining Silesia, Inflanty (Livonia), incorporation of Ducal Prussia, creation of his hereditary dukedom etc.), some of them with real chances of success, but because of bad luck or objective obstacles almost nothing went as he planned.
Wladislaw died in
1648. His heart and
viscera were interred in the Chapel of
St. Casimir of
Vilnius Cathedral, which he himself had commissioned. A year after the death of his son, on the eve of the
Chmielnicki Uprising and
The Deluge. He failed to realize his dreams of conquest and he did not reform the Commonwealth. Wladislaw managed to avoid involving the Commonwealth in the bloody Thirty Year's War but his legacy would end the Golden Era of the Commonwealth. The Cossacks, angered because Wladislaw's promises to them failed to materialize, were beginning their greatest revolt against Polish rule, which would be exploited by Swedish invasion.
