tip the balance/scales

tip the balance

To upset the balance of a situation, such that one side or element is favored or gains advantage. The two candidates are so close in the polls that both are vying for something that will tip the balance in their favor. The immense interconnectivity of social media has tipped the balance of power somewhat back into the hands of the ordinary population.
See also: balance, tip
Farlex Dictionary of Idioms.

tip the balance

Also, tip the scales; turn the scale. Offset the balance and thereby favor one side or precipitate an action. For example, He felt that affirmative action had tipped the balance slightly in favor of minority groups , or New high-tech weapons definitely tipped the scales in the Gulf War, or Just one more mistake will turn the scale against them. Shakespeare used turn the scale literally in Measure for Measure (4:2): "You weigh equally; a feather will turn the scale." The idioms with tip are much younger, dating from the first half of the 1900s.
See also: balance, tip
The American Heritage® Dictionary of Idioms by Christine Ammer.

tip the balance

or

tip the scales

COMMON If something tips the balance or tips the scales in a situation where two results seem equally likely, it makes one result happen or become much more likely. As the election approaches, the two main parties appear so evenly matched that just one issue could tip the balance. Years later, she still believed it had been Howe's warnings, not any love for her, that had finally tipped the scales against his leaving her for Lucy.
See also: balance, tip
Collins COBUILD Idioms Dictionary, 3rd ed.

tip (or turn) the scales (or balance)

(of a circumstance or event) be the deciding factor; make the critical difference.
See also: Scales, tip
Farlex Partner Idioms Dictionary

tip the ˈbalance/ˈscales

(also swing the ˈbalance) be the reason that finally causes somebody to do something or something to happen in one way rather than another: They were both very good candidates for the job but she had more experience and that tipped the balance.
See also: balance, Scales, tip
Farlex Partner Idioms Dictionary

tip the scales

1. To register weight (at a certain amount).
2. To offset the balance of a situation.
See also: Scales, tip
American Heritage® Dictionary of the English Language, Fifth Edition.
See also:
  • gut factor
  • in (one's) element
  • in element
  • in one's element
  • in your element
  • be in (one's) element
  • element
  • one rotten apple spoils the (whole) barrel
  • one rotten apple spoils the (whole) bushel
  • rotten apple spoils the barrel