Arguments Against Trade Protection

Misallocation of Resources: As tariffs or quotas are put in place, social surplus decreases, and the market becomes allocatively inefficient, wasting some resources.

Retaliation: As one country puts a trade protection in place, other countries may do the same in protest.

Higher Prices: Trade barriers raise prices (as seen on the supply-demand diagrams here).

Increased Costs: As prices increase, the cost of living will also. Since this will also impact costs for businesses, they may not afford employees, lowering employment (instead of an intended effect of protection, being protection of jobs)

Less Choice: With imports being disincentivized, there will be less of them present, which reduces the amount of options consumers have.

Domestic Firms Lack Incentive to Become More Efficient: When they have the advantage given to them by the government, why would they need to innovate?

Reduced Export Competitiveness: Because of this lack of incentive to innovate and become more efficient, domestic firms' goods and services will not be very competitive in other countries, reducing their exports.