経済の文献を読んでてわからない文があったのでわかる方、訳教えてください。
That protectionizm helped kill both the customs union with Italy, which the two had informally agreed in March
1949, and the loose schemes of cooperation with Italy and the Benelux countries whichwere being discussed.
（参考）
protectionizm：保護貿易主義
customs union：関税同盟
Benelux countries：ベネルクス三国
