Traditional Culture Encyclopedia - Photography major - Jefferson will run for office in an old T-shirt and jeans.

Jefferson will run for office in an old T-shirt and jeans.

Jefferson will run for office in his old shirt and jeans.

The subjunctive mood of "would+have+done" indicates the assumption of the past, which means "I did it long ago".

"could+have+done" is subjunctive, which means that you could have done something, but you didn't.