diff --git a/gamecore.cpp b/gamecore.cpp
index 08035dd..79c519d 100644
--- a/gamecore.cpp
+++ b/gamecore.cpp
@@ -3,7 +3,6 @@
 #include "debug.h"
 #include <SDL.h>
 
-int GameCore::MAX_MOVE_DISTANCE = 100;
 int GameCore::NODE_RADIUS = 12;
 
 GameCore::GameCore()
@@ -22,7 +21,7 @@ int GameCore::execute()
 	while(SDL_PollEvent(&event))
 	    handle_event(&event);
 	//	iterate();
-	renderer.render(data, MAX_MOVE_DISTANCE);
+	renderer.render(data);
     }
 
     cleanup();
@@ -54,15 +53,6 @@ void GameCore::on_exit()
 
 void GameCore::on_lbutton_down(int x, int y)
 {
-    Vertex* cv = data.get_current_vertex();
-    if (cv != NULL &&
-	(MathUtils::distance(cv->x, cv->y, x, y)
-	 > MAX_MOVE_DISTANCE))
-    {
-	data.select_vertex(x, y);
-	return;
-    }
-
     data.do_vertex(x, y, NODE_RADIUS);
 }
 
@@ -76,4 +66,6 @@ void GameCore::on_rbutton_down(int mX, int mY)
 void GameCore::on_key_down(SDLKey sym, SDLMod mod, Uint16 unicode)
 {
     if (sym == SDLK_q && mod & KMOD_CTRL) is_running = false;
+    if (sym == SDLK_a) data.set_mode(MODE_ATTACK);
+    if (sym == SDLK_m) data.set_mode(MODE_MOVE);
 }
diff --git a/gamedata.cpp b/gamedata.cpp
index ae8d95a..8357431 100644
--- a/gamedata.cpp
+++ b/gamedata.cpp
@@ -15,6 +15,7 @@ GameData::GameData()
 {
     current = NULL;
     player = PLAYER1;
+    mode = MODE_MOVE;
 }
 
 GameData::~GameData() { }
@@ -23,17 +24,29 @@ void GameData::toggle_turn()
 {
     if (player == PLAYER1) player = PLAYER2;
     else if (player == PLAYER2) player = PLAYER1;
+    mode = MODE_MOVE;
 }
 
 
 void GameData::do_vertex(int x, int y, int r)
 {
-    int colour;
-    if (player == PLAYER1) colour = PLAYER1_COLOUR;
-    if (player == PLAYER2) colour = PLAYER2_COLOUR;
+    if (current != NULL &&
+	(MathUtils::distance(current->x, current->y, x, y)
+	 > get_move_radius()))
+    {
+	select_vertex(x, y);
+	return;
+    }
 
-    if (point_in_vertex(x, y, r)) select_vertex(x, y);
-    else add_vertex(x, y, r, colour);
+    if (mode == MODE_MOVE)
+    {
+	int colour;
+	if (player == PLAYER1) colour = PLAYER1_COLOUR;
+	if (player == PLAYER2) colour = PLAYER2_COLOUR;
+
+	if (point_in_vertex(x, y, r)) select_vertex(x, y);
+	else add_vertex(x, y, r, colour);
+    }
 }
 
 
@@ -57,6 +70,8 @@ void GameData::select_vertex(int x, int y)
 
 bool GameData::add_vertex(int x, int y, int r, int colour)
 {
+    if (mode == MODE_ATTACK) return false;
+
     // this is the special case for adding the first vertex for each player
     if (current == NULL)
     {
@@ -152,3 +167,10 @@ float GameData::calculate_strength_r(Vertex* node, unsigned int depth, list<Vert
 
     return modscore;
 }
+
+
+int GameData::get_move_radius(Vertex* node)
+{
+    if (current == NULL) return 0;
+    else return 100;
+}
diff --git a/gamedata.h b/gamedata.h
index 563cf3c..af0289f 100644
--- a/gamedata.h
+++ b/gamedata.h
@@ -9,7 +9,7 @@
 #include "graph.h"
 
 enum Turn {PLAYER1, PLAYER2, WIN1, WIN2};
-
+enum Mode {MODE_MOVE, MODE_ATTACK};
 
 class GameData : public Graph
 {
@@ -28,12 +28,20 @@ class GameData : public Graph
 
     bool add_vertex(int x, int y, int r, int colour);
 
+    Mode get_mode() const { return mode; }
+    Mode set_mode(Mode m) { mode = m; }
+
+    // returns the move/attack radius (based on mode) for the specified node
+    // (or the selected node if node == NULL)
+    int get_move_radius(Vertex* node = NULL);
+
  private:
     float calculate_strength(Vertex* node);
     float calculate_strength_r(Vertex* node, unsigned int depth, list<Vertex*>& visited);
 
     Vertex* current;
     Turn player;
+    Mode mode;
     bool player1_played;
     bool player2_played;