In the beginning was the Word, and the Word was with God, and the Word was God. (John 1:1 ESV)
In the Watchtower article Is Jesus God? they quote A. T. Robertson as part of building their case that John 1:1 does not teach Jesus is God. This is very deceptive because if we let A. T. Robertson speak for himself on John 1:1 he says this:
And the Word was God (kai theos ēn ho logos). By exact and careful language John denied Sabellianism by not saying ho theos ēn ho logos. That would mean that all of God was expressed in ho logos and the terms would be interchangeable, each having the article. The subject is made plain by the article (ho logos) and the predicate without it (theos) just as in Joh 4:24 pneuma ho theos can only mean “God is spirit,” not “spirit is God.” So in 1Jo 4:16 ho theos agapē estin can only mean “God is love,” not “love is God” as a so-called Christian scientist would confusedly say. For the article with the predicate see Robertson, Grammar, pp. 767f. So in Joh 1:14 ho Logos sarx egeneto, “the Word became flesh,” not “the flesh became Word.” Luther argues that here John disposes of Arianism also because the Logos was eternally God, fellowship of Father and Son, what Origen called the Eternal Generation of the Son (each necessary to the other). Thus in the Trinity we see personal fellowship on an equality.
A. T. Robertson is correct here. John 1:1 affirms the deity of Christ while rejecting modalism. John 1:1 is a clear verse in favor of the trinity. It is very clear that John understood the doctrine of the trinity and carefully recorded it under inspiration of the Holy Spirit so we too would understand it.
The Jehovah’s Witnesses did not always deny that Jesus is God. In 1945 225,302 Jehovah’s Witnesses voted to pass their amended charter which states that a purpose of the Watchtower is to worship Jesus. While disallowing worship of anything but God, we must conclude that in 1945 the Watchtower believed Jesus to be God.