The House is suppose to present the facts of the impeachment. Why didn't they call witnesses for Trump in the House? Simple answer and not many people are given the FACTS which is the fault of the GOP especially. The Executive branch has a RIGHT to take the House witness requests to SCOTUS. But the Democrats didn't want to have this go to SCOTUS for one reason. Time. The Democrats wanted to speed up the impeachment process and since they had the majority in the house there was no need. So now the Senate does NOT need any more witnesses.