diff --git a/syndicate/broker/federation2.rkt b/syndicate/broker/federation2.rkt
index 39d7a7f..26e9743 100644
--- a/syndicate/broker/federation2.rkt
+++ b/syndicate/broker/federation2.rkt
@@ -80,48 +80,50 @@
            (begin/dataflow (log-syndicate/federation-debug "::: ~a specs ~v" nodeid (specs)))
            (begin/dataflow (log-syndicate/federation-debug "::: ~a subs ~v" nodeid (subs))))
 
-         (define-syntax with-localid->sub
-           (syntax-rules (->)
-             ((_ (localid connid -> sub) body ...)
-              (match (hash-ref (subs) localid #f)
-                [#f (log-syndicate/federation-error
-                     "Mention of nonexistent local ID ~v from connection ~v. Ignoring."
-                     localid
-                     connid)]
-                [sub body ...]))))
+         (define (call-with-sub localid connid f)
+           (match (hash-ref (subs) localid #f)
+             [#f (log-syndicate/federation-error
+                  "Mention of nonexistent local ID ~v from connection ~v. Ignoring."
+                  localid
+                  connid)]
+             [sub (f sub)]))
 
          (define (unsubscribe! localid connid)
-           (with-localid->sub [localid connid -> sub]
-             (define new-holders (hash-remove (subscription-holders sub) connid))
-             (specs (hash-remove (specs) (subscription-spec sub)))
-             (subs (if (hash-empty? new-holders)
-                       (hash-remove (subs) localid)
-                       (hash-set (subs) localid (struct-copy subscription sub
-                                                  [holders new-holders]))))
+           (call-with-sub
+            localid connid
+            (lambda (sub)
+              (define new-holders (hash-remove (subscription-holders sub) connid))
+              (specs (hash-remove (specs) (subscription-spec sub)))
+              (subs (if (hash-empty? new-holders)
+                        (hash-remove (subs) localid)
+                        (hash-set (subs) localid (struct-copy subscription sub
+                                                   [holders new-holders]))))
 
-           ;; The messages we send depend on (hash-count new-holders):
-           ;;  - if >1, there are enough other active subscribers that we don't need to send
-           ;;    any messages.
-           ;;  - if =1, we retract the subscription from that peer (INVARIANT: will not be connid)
-           ;;  - if =0, we retract the subscription from all peers except connid
+              ;; The messages we send depend on (hash-count new-holders):
+              ;;  - if >1, there are enough other active subscribers that we don't need to send
+              ;;    any messages.
+              ;;  - if =1, we retract the subscription from that peer (INVARIANT: will not be connid)
+              ;;  - if =0, we retract the subscription from all peers except connid
 
-             (match (hash-count new-holders)
-               [0 (for [(peer (in-set (peers)))]
-                    (when (not (equal? peer connid))
-                      (send! (router-outbound peer (Unsubscribe localid)))))]
-               [1 (for [(peer (in-hash-keys new-holders))] ;; there will only be one, ≠ connid
-                    (send! (router-outbound peer (Unsubscribe localid))))]
-               [_ (void)])))
+              (match (hash-count new-holders)
+                [0 (for [(peer (in-set (peers)))]
+                     (when (not (equal? peer connid))
+                       (send! (router-outbound peer (Unsubscribe localid)))))]
+                [1 (for [(peer (in-hash-keys new-holders))] ;; there will only be one, ≠ connid
+                     (send! (router-outbound peer (Unsubscribe localid))))]
+                [_ (void)]))))
 
          (define (adjust-matches localid connid captures delta expected-outcome ctor)
-           (with-localid->sub [localid connid -> sub]
-             (define-values (new-matches outcome)
-               (bag-change (subscription-matches sub) captures delta #:clamp? #t))
-             (subs (hash-set (subs) localid (struct-copy subscription sub [matches new-matches])))
-             (when (eq? outcome expected-outcome)
-               (for ([(peer peer-subid) (in-hash (subscription-holders sub))])
-                 (when (not (equal? peer connid))
-                   (send! (router-outbound peer (ctor peer-subid captures))))))))
+           (call-with-sub
+            localid connid
+            (lambda (sub)
+              (define-values (new-matches outcome)
+                (bag-change (subscription-matches sub) captures delta #:clamp? #t))
+              (subs (hash-set (subs) localid (struct-copy subscription sub [matches new-matches])))
+              (when (eq? outcome expected-outcome)
+                (for ([(peer peer-subid) (in-hash (subscription-holders sub))])
+                  (when (not (equal? peer connid))
+                    (send! (router-outbound peer (ctor peer-subid captures)))))))))
 
          (during (observe (router-connection nodeid $connid))
            (assert (router-connection nodeid connid))
@@ -215,9 +217,11 @@
                (relay-add-or-del localid captures -1 'present->absent Del))
 
            (on (message (router-inbound connid (Msg $localid $captures)))
-               (with-localid->sub [localid connid -> sub]
-                 (for ([(peer peer-subid) (in-hash (subscription-holders sub))])
-                   (when (not (equal? peer connid))
-                     (send! (router-outbound peer (Msg peer-subid captures)))))))
+               (call-with-sub
+                localid connid
+                (lambda (sub)
+                  (for ([(peer peer-subid) (in-hash (subscription-holders sub))])
+                    (when (not (equal? peer connid))
+                      (send! (router-outbound peer (Msg peer-subid captures))))))))
 
            )))