Final answer:
In a contested convention, delegates cast multiple ballots at the party's national convention until a candidate secures the majority of votes required for the nomination.
Step-by-step explanation:
The process for picking a candidate in the case of a contested convention is not through a nationwide primary, nor is it determined solely by members of Congress from that party or by superdelegates. Instead, the delegates at the national convention cast multiple ballots until a candidate has a majority of votes. This happens during the national convention of the political party, which is an event signaling the transition from primary elections to the general election. During this convention, delegates from all states debate, vote on the party’s platform, and officially cast their ballots based on the prior results of primaries or caucuses. If no candidate has received the majority of delegates' support through primaries and caucuses, the delegates will continue with additional rounds of voting until one emerges with the majority required to secure the nomination.