So it is that June – despite the lack of hostile summits in that month – can be seen as a turning point in the intra-Soviet bloc crisis. This is not because there were any significant changes of position on any side. On the contrary, what became increasingly apparent, particularly between the Soviet and Czechoslovak leaders, was that the counterparts were insistent and unmoving in both their perspectives on events within Czechoslovakia and their prescriptions for what ought to be done about it. The indications of this intransigence on each side, for the Czechoslovak reformers and the Soviet leaders, caused a heightening sense of pressure and a hardening of positions. Therefore, the more the Soviets regarded Dubček and his allies as persistently unwilling and unable to take what they regarded as the necessary actions in Czechoslovakia, the greater urgency they felt to force the issue.

This urgency was also given focus by a political deadline that emerged in Czechoslovakia. At the end of May, the KSČ Central Committee agreed to exercise its prerogative to convene an extraordinary party congress (the 14th) on 9 September. Party congresses were usually gathered every five years in Czechoslovakia and were the de jure supreme authority of the party that elected the Central Committee. The previous one had been held just two years earlier in 1966, but Dubček and his allies clearly saw a special congress as a way to remove remaining hardliners from the Central Committee and smooth the domestic path to reform. ‘If permitted to hold the congress,’ Dubcek wrote later, ‘the reform forces would gain decisive control of leading Party organs; that would, at the same time, substantially reduce the Soviet fifth column in the Party.’ Therefore, as the Czechoslovak leaders experienced unyielding and intensifying pressure from the Soviet Union on behalf of the measures Brezhnev insisted upon, it had the opposite effect to that which was intended. It strengthened KSČ reformers’ determination to pursue what they regarded as the right path, bolstered by an indignation at Soviet meddling that was shared by the press and public. With the 9 September deadline in mind, Dubček thought that just a few more months’ persistence and resistance of Soviet pressure could set Czechoslovakia's direction beyond reversal, and the quibbling and pressure of the Soviets would be rendered moot.