Operation Killing Stroke
Operation Killing Stroke was a military plan for a three-pronged assault by the Free Worlds League into the Lyran Commonwealth intended to culminate in the capture of Denebola, Solaris and Wyatt. 
Within a year of ascending to the office of Captain-General, Thaddeus Marik had instructed his generals to begin plans for a three-pronged invasion of the Lyran Commonwealth, with the main objective being the capture of Solaris and the former Terran Hegemony worlds of Denebola and Wyatt.
Thaddeus' demand in early 2950 that the Free Worlds League Parliament commit 30 regiments of troops and extensive funding to enact Operation Killing Stroke was firmly rejected. Parliament didn't stop with rejecting the Captain-General's demand; it voted that such an invasion of the Commonwealth would place worlds within two jumps of the Lyran and Capellan borders under threat of invasion, placing all of the troops from those worlds under the terms of the Home Defense Act.
A dozen principalities invoked the Act for the very first time in response to the vote in Parliament, including the Duchy of Andurien, the Sirian Concordat and the Stewart Commonwealth, which promptly removed 18 regiments originally earmarked for the plan, almost two-thirds of the intended invasion force  
Despite the opposition of both Parliament and others, Thaddeus wouldn't be dissuaded from his grand venture; he began his attempts to gain the support he needed by moving units of the Marik Militia into the small states of Nestor and Talitha, using the pretext of quelling domestic emergencies to remove government leaders likely to be in opposition to him and replacing them with individuals more inclined to follow his line.
Thaddeus followed this by using personal funds to hire 10 regiments of mercenaries including Carson's Renegades, the Langendorf Lancers and Redmond's Broadswords and by issuing declarations that only worlds contributing troops to the operation would share in any resulting booty. A few more worlds entered the fold following his declaration, and Thaddeus finally launched a truncated version of his original offensive.
One of the most costly and least successful military operations mounted by the FWLM, the main consequence of Operation Killing Stroke was that it pushed a number of worlds within the Free Worlds League to create mutual defence pacts that ultimately became the coalition known as the Silver Hawks with the ratification of the Concord of Danais in 2966. 
- House Marik: The Free Worlds League, p. 42
- Handbook: House Marik, p.41
- Field Manual: Free Worlds League, p. 8 "A House Divided - Poltics of Command - Resolution 288"
- House Marik: The Free Worlds League, p. 43