αποφασιστικότητα της κυβέρνησης να συμπαραταχθεί
The problem here is the να, a useful "all-purpose" connector in Greek, but with no single equivalent in English. What determines the choice for the translator is what word is used for αποφασιστικότητα. It then becomes a matter of English grammar, and not of "what the Greek says".
Stavropoulos gives decisiveness, resoluteness, resolution, determination, stoutness as English equivalents. Ignoring the last of these, which does not suit this context, what distinction can we make between the others, or are they interchangeable in this context?
"we do not share the determination of our government to align itself with the Western alliance"
"we do not share the decisiveness of our government in aligning itself with the Western alliance"
The first of these implies that the government is planning to do this, but has not yet done it. The second that it has already aligned itself with the western alliance. Which of these fits the meaning of the Greek text in this context? How could you use determination or decisiveness with the opposite meanings?
"we do not share the determination our government has shown in aligning itself ..."
"we do not share the decisiveness our government is demonstrating by aligning itself..."
the use of in + ing-form can be glossed in Greek as με το που το κάνει αυτό, in other words we are talking about a fact rather than a wish or hypothesis.