Lee took a gamble and lost.
Perhaps he feared that rather than attack him Meade would simply try to blockade him while the Army of the Potomac (savaged at Fredericksburg and Chancellorsville) was rebuilt. But all he would have had to do was send Jeb Stuart's cavalry on a raid towards Washington and they would have been all over Meade's ass to move on Lee. I don't know.
Perhaps he feared that rather than attack him Meade would simply try to blockade him while the Army of the Potomac (savaged at Fredericksburg and Chancellorsville) was rebuilt. But all he would have had to do was send Jeb Stuart's cavalry on a raid towards Washington and they would have been all over Meade's ass to move on Lee. I don't know.