Earlier in the day, the CDU supported party chairman Laschet for the German chancellorship by a majority vote. CSU head Markus Soeder accepted the decision.
"I think everyone wants the Union [CDU/CSU] to succeed and everyone knows what is at stake, what we are talking about is a decision on the course of Germany's development. If the Red-Red-Green coalition [the Social Democrats, Die Linke and the Green party] comes to power, it will be a different republic," Laschet told reporters.
Speaking about his rivalry with Soeder for the right to run in the elections, Laschet stressed that it was a transparent process and that the coalition would remain united.
"The CDU will not win the elections without the CSU and vice versa," the politician said, adding that Soeder would play a central role in German politics.
Asked whether the power struggle between the CDU and CSU leaders caused any collateral damage to the parties, Laschet declined to comment.
Elections to the Bundestag will be held on September 26, 2021. Incumbent Chancellor Angela Merkel has repeatedly stated that her current term in office will be her last.