What a surprise it didn’t need nuclear ordinance or building giant elaborate dams or millions of helicopters.
It's been blocked before but for a lot longer (from late 1956 to early 1957—about five months) during the Suez Crisis: https://en.wikipedia.org/wiki/Suez_Crisis That was a really big deal—more so than this one, I still remember the daily radio news reports and huge newspaper headlines from when I was a young kid. It was an international crisis that dragged on for months and months.
A well hidden explosive charge on a container ship in the canal could cause a multi-month blockage - perhaps longer.
It would probably be smart to dig a 2nd channel.