For Republicans, Deep Wounds Fuel Resistance to Bolstering the I.R.S.

A desire to crack down on tax cheats is overshadowed by years of G.O.P. resentment toward the agency.

WASHINGTON — A plan by Democrats to pay for infrastructure investments by beefing up the Internal Revenue Service to catch tax evaders has resurfaced old resentments for Republicans, whose distrust of the agency has simmered for years, erasing hopes of a bipartisan legislative accord built on narrowing the so-called tax gap. Republican senators backed away this week from a provision to toughen tax enforcement at the I.R.S., gutting a crucial source of financing for an infrastructure package that would devote about $600 billion to roads, bridges, broadband and other public goods. That has left lawmakers scrambling to figure out how to pay for the legislation and has again put the I.R.S., whose funding and ability to conduct audits has diminished over the past decade, in limbo. For conservative activists, who have harbored enmity toward the I.R.S. for more than a decade, the agency is considered a threat that is beyond reclamation.