diff --git a/lift.go b/lift.go
index 7212945..47e18f0 100644
--- a/lift.go
+++ b/lift.go
@@ -6,8 +6,12 @@ import (
 	"strings"
 )
 
+// LiftedArgs represents a set of variables that have been lifted from expressions and
+// replaced with identifiers, eg `id == "foo"` becomes `id == vars.a`, with "foo" lifted
+// as "vars.a".
 type LiftedArgs interface {
 	Get(val string) (any, bool)
+	Map() map[string]any
 }
 
 // liftLiterals lifts quoted literals into variables, allowing us to normalize
@@ -128,6 +132,14 @@ type pointerArgMap struct {
 	vars map[string]argMapValue
 }
 
+func (p pointerArgMap) Map() map[string]any {
+	res := map[string]any{}
+	for k, v := range p.vars {
+		res[k] = v.get(p.expr)
+	}
+	return res
+}
+
 func (p pointerArgMap) Get(key string) (any, bool) {
 	val, ok := p.vars[key]
 	if !ok {
@@ -151,3 +163,7 @@ func (p regularArgMap) Get(key string) (any, bool) {
 	val, ok := p[key]
 	return val, ok
 }
+
+func (p regularArgMap) Map() map[string]any {
+	return p
+}
diff --git a/parser.go b/parser.go
index 12b8a82..1793a21 100644
--- a/parser.go
+++ b/parser.go
@@ -545,7 +545,7 @@ func callToPredicate(item celast.Expr, negated bool, vars LiftedArgs) *Predicate
 			}
 		}
 
-		if aIsVar {
+		if aIsVar && vars != nil {
 			if val, ok := vars.Get(strings.TrimPrefix(identA, VarPrefix)); ok {
 				// Normalize.
 				literal = val
@@ -554,7 +554,7 @@ func callToPredicate(item celast.Expr, negated bool, vars LiftedArgs) *Predicate
 			}
 		}
 
-		if bIsVar {
+		if bIsVar && vars != nil {
 			if val, ok := vars.Get(strings.TrimPrefix(identB, VarPrefix)); ok {
 				// Normalize.
 				literal = val
diff --git a/parser_test.go b/parser_test.go
index cf5452a..15d9db1 100644
--- a/parser_test.go
+++ b/parser_test.go
@@ -963,6 +963,9 @@ func TestParse_LiftedVars(t *testing.T) {
 				test.expected.Evaluable = eval
 			}
 
+			// Convert the lifted arg interfaces to the same map values
+			actual.Vars = regularArgMap(actual.Vars.Map())
+
 			require.NoError(t, err)
 			require.NotNil(t, actual)