diff --git a/ipn/local.go b/ipn/local.go
index ad11fe202..16934eb8e 100644
--- a/ipn/local.go
+++ b/ipn/local.go
@@ -1154,6 +1154,7 @@ func (b *LocalBackend) authReconfig() {
 	uc := b.prefs
 	nm := b.netMap
 	hasPAC := b.prevIfState.HasPAC()
+	disableSubnetsIfPAC := nm != nil && nm.Debug != nil && nm.Debug.DisableSubnetsIfPAC.EqualBool(true)
 	b.mu.Unlock()
 
 	if blocked {
@@ -1178,13 +1179,7 @@ func (b *LocalBackend) authReconfig() {
 	if uc.AllowSingleHosts {
 		flags |= controlclient.AllowSingleHosts
 	}
-	if hasPAC {
-		// TODO(bradfitz): make this policy configurable per
-		// domain, flesh out all the edge cases where subnet
-		// routes might shadow corp HTTP proxies, DNS servers,
-		// domain controllers, etc. For now we just want
-		// Tailscale to stay enabled while laptops roam
-		// between corp & non-corp networks.
+	if hasPAC && disableSubnetsIfPAC {
 		if flags&controlclient.AllowSubnetRoutes != 0 {
 			b.logf("authReconfig: have PAC; disabling subnet routes")
 			flags &^= controlclient.AllowSubnetRoutes
diff --git a/tailcfg/tailcfg.go b/tailcfg/tailcfg.go
index fa4c46cf3..bab6f6048 100644
--- a/tailcfg/tailcfg.go
+++ b/tailcfg/tailcfg.go
@@ -660,6 +660,10 @@ type Debug struct {
 	// TrimWGConfig controls whether Tailscale does lazy, on-demand
 	// wireguard configuration of peers.
 	TrimWGConfig opt.Bool `json:",omitempty"`
+
+	// DisableSubnetsIfPAC controls whether subnet routers should be
+	// disabled if WPAD is present on the network.
+	DisableSubnetsIfPAC opt.Bool `json:",omitempty"`
 }
 
 func (k MachineKey) String() string                   { return fmt.Sprintf("mkey:%x", k[:]) }