Historical clue formulations

• Battle of Vicksburg in the Civil War, e.g. — 2026-01-14
• Invader's tactic — 2025-09-18
• Prolonged attack — 2024-03-20
• Drawn-out military attack — 2023-10-17
• Prolonged attack — 2023-09-12
• Drawn-out attack — 2022-11-28
• Lengthy attack — 2022-10-04
• Campaign that may involve catapults and trebuchets — 2021-07-24
• Alternative to a blitz — 2021-05-16
• Military operation that might last for months — 2019-03-12
• The Alamo had a famous one — 2019-02-14
• Lengthy attack — 2018-08-05
• Military action that includes a blockade — 2018-07-10
• Battle of Leningrad, e.g. — 2018-06-17
• All-out attack — 2018-05-06
• Long, drawn-out fight — 2018-05-01
• Tactic in a war of attrition — 2018-02-18
• Counterpart of a blitz — 2017-09-09
• Drawn-out campaign — 2017-06-17
• Attack on a walled city, maybe — 2017-01-11
• Prolonged attack — 2015-12-01
• Genghis Khan tactic — 2015-04-23
• Lengthy bout — 2015-03-13
• Battle of the Alamo, e.g. — 2015-02-15
• Challenge for defenders — 2014-09-27
• Prolonged attack — 2013-09-09
• Military blockade — 2013-08-11
• Long bout — 2012-12-21
• Kind of mentality — 2012-08-25
• Long, drawn-out attack — 2012-04-09
• You're being attacked while under it — 2012-03-28
• Tactic for Napoleon — 2011-04-14
• More than a raid — 2010-03-25
• Long period, as of illness — 2009-12-11
• Attack tactic — 2009-10-04
• Campaign against Troy, e.g. — 2009-06-17
• Prolonged attack — 2009-01-19
• Assault on Troy, e.g. — 2008-09-16
• ___ of Leningrad, 1941-44 — 2007-02-21
• Prolonged attack — 2007-02-12
• Long, drawn-out attack — 2006-08-07
• Crusades tactic — 2006-03-02
• War tactic — 2006-01-08
• Assault on Troy, e.g. — 2005-10-26
• Drawn-out fight — 2005-06-12
• Preattack tactic — 2005-03-06
• Long series of troubles — 2005-03-04
• Operation at the Alamo — 2004-02-17
• More than a 23-Across — 2003-04-26
• Warfare tactic — 2003-04-18