How does weak party discipline make it difficult for federal government to enact public policy?

Weak Party Discipline makes it difficult to enact public policy because of individuals' inability to follow the party policies. Traditionally party members set an agenda in a caucus and agree on this policy, and this policy is enforced by the Party Whip ( the policy maintainer) however some outliers in a party can choose to disagree on there own free will. This causes cohesion on an issue to falter and a party grows less and less stable. If a majority is needed to pass a bill, and a party already needs to convince a few members of the opposition to join their side having weakly disciplined party members only increases their chance that the bill will end up in gridlock and possibly be killed.