diff --git a/ethereum/contracts/core/Forum.sol b/ethereum/contracts/core/Forum.sol
index 667e2c5..32e249b 100644
--- a/ethereum/contracts/core/Forum.sol
+++ b/ethereum/contracts/core/Forum.sol
@@ -36,6 +36,17 @@ contract Forum is Reputation {
         for (uint i = 0; i < citations.length; i++) {
             post.citations.push(citations[i]);
         }
+        int totalCitationWeightAbs;
+        for (uint i = 0; i < post.citations.length; i++) {
+            int weight = post.citations[i].weightPercent;
+            require(weight >= -100, "Each citation weight must be >= -100");
+            require(weight <= 100, "Each citation weight must be <= 100");
+            totalCitationWeightAbs += weight > 0 ? weight : -weight;
+        }
+        require(
+            totalCitationWeightAbs <= 100,
+            "Sum of absolute value of citations must be <= 100"
+        );
         emit PostAdded(postIndex);
     }
 
@@ -45,10 +56,6 @@ contract Forum is Reputation {
 
     function _propagateValue(uint postIndex, int amount) internal {
         Post storage post = posts[postIndex];
-        int totalCitationWeight;
-        for (uint i = 0; i < post.citations.length; i++) {
-            totalCitationWeight += post.citations[i].weightPercent;
-        }
         int totalOutboundAmount;
         for (uint i = 0; i < post.citations.length; i++) {
             int share = (amount * post.citations[i].weightPercent) / 100;