Well here is the update finally
Official complaints to Colombia have been sent; apparently they are aiding Panama rebels, and it is possible they are aligning with the US. They deny all allegations, but even I have to admit it is a little suspicious, allowing the remnants of the Panama army to escape into their borders.
But before we could anything at all, the US began a massive counter attack. Our divisions - who were preparing for an invasion of Panama - were taken completely off guard. Nobody expected the US to mount any offensive so quickly.
They managed to ship in more divisions and supplies into the port as our forces struggled to reach the canal. As our forces reach the port, the US is fighting to the bitter end.
Whilst we were fighting in the canal, the US and Panama had set up a temporary government to hold off the attack, presumably until US reinforcements arrive. They can still land anywhere on the US side of the coast.
Luckily, the forces Panama had at its disposal were simply men rallied together, and the US marine divisions there had just come out of battle, so we have managed to take back the canal.
With Panama defeated for a second time, we have turned our attention to Colombia once again. I haven't been told anything directly, but I've heard our army is once again on their borders. This time, we've left a small force to defend the canal in case the US tries that again.
And just as I predicted, we've declared war on Colombia. Here we go, yet again. At least there won't be any naval battles for a while, so I can rest.