diff --git a/amanuensis/server/forms.py b/amanuensis/server/forms.py
index fad112f..c7feb7d 100644
--- a/amanuensis/server/forms.py
+++ b/amanuensis/server/forms.py
@@ -125,6 +125,10 @@ class LexiconConfigForm(FlaskForm):
 	# And finally, the submit button
 	submit = SubmitField("Submit")
 
+	def validate_publishDeadlines(form, field):
+		if form.publishAsap.data:
+			raise ValidationError('Cannot specify deadline if immediate publishing is enabled')
+
 	# TODO add validators that call into extant valid check methods
 
 	def set_options(self, lexicon):
diff --git a/amanuensis/templates/lexicon/settings.html b/amanuensis/templates/lexicon/settings.html
index 6598d6b..6a937c7 100644
--- a/amanuensis/templates/lexicon/settings.html
+++ b/amanuensis/templates/lexicon/settings.html
@@ -84,6 +84,9 @@
 		{{ form.publishDeadlines(autocomplete="off") }}
 		{{ form.publishDeadlines.label }}<br>
 		{{ flag_setting(form.publishAsap) }}
+		{% for error in form.publishDeadlines.errors %}
+		<span style="color: #ff0000">{{ error }}</span><br>
+		{% endfor %}
 		{{ flag_setting(form.publishBlockOnReady) }}
 		{{ number_setting(form.publishQuorum) }}
 	</p>