…ば…だろう

Speculates about an event that one thinks could have occurred if the situation had been different. The final sentence often uses conjectural or predictive expressions such as (だろう / はずだ / かもしれない / にちがいない / と思う). If the predicate of the sentence is in the past tense, it indicates that the reality in the past was different from the described event. If the predicate is in the dictionary form (present tense), it indicates that the current situation would be different.