in 1932, wijnkoop targeted dutch envoy to china frans beelaerts van blokland on the dutch attitude towards the situation in shanghai., and later in 1932 against minister john paul reymer on the wages of railway employees and the proposed wage reductions. afterwards, in 1935, he worked against minister of public works otto van lidth de jeude, in support of the interference of government in the conflict with privately owned mines. in 1938, he fought against government minister jacob patijn on the recognition of the king of italy as emperor of ethiopia. in 1939, he clashed with the government again, this time against minister of justice carel goseling on the cooperation of the netherlands to supply the needs of spanish refugees during the spanish civil war. finally, in 1939, he talked with prime minister hendrikus colijn about the cause of the resignation of the minister of finance and the resulting consequences of his resignation.