支持开罗宣言效力的人士则主张:
1. 开罗宣言是历史事实
2. 开罗宣言原件当然存在: 原存于U.S. National Archives & Records Administration (RG59)。开罗宣言原文收录在美国国务院出版的美国条约汇编(参阅: charles i. bevans, treaty and other international agreements of the united states of america 1776-1949, vol. 3, multilateral,1931-1945, washington, d.c.: us )，日本国会图书馆已经影印保存，网页上也有原件扫描文件。另外在日本外务省所汇编的「日本外交年表并主要文书」下卷也有官方译文。美国国务院，日本国会图书馆与日本外务省并不代表统派。
3. 开罗宣言是当时中美英三国领导人共识:见「《美国对外关系文件》FRUS1943 开罗和德黑兰」一节，有议定过程。美国对外关系文件一书并不代表统派。
4. 国际法中，国际条约效力并不单看签字与否:可参见一般的国际法教科书，或维也纳条约法公约第十一条:一国承受条约拘束之同意得以签署、交换构成条约之文书，批准、接受、赞同或加入，或任何其它同意之方式表示之。日本降书承诺要实行《波茨坦宣言》，《波茨坦宣言》承诺要实行「开罗宣言」。维也纳条约法公约并不代表统派。
5. 国际法中，公约,条约,宣言,公报,议定书,..等,都可以视为国际条约:可参见一般的国际法教科书，或维也纳条约法公约第二条:称『条约』者，谓国家间所缔结而以国际法为准之国际书面协议，不论其载于一项单独文书或两项以上相互有关之文书内，亦不论其特定名称如何；。维也纳条约法公约并不代表统派。
6. 开罗宣言业已经过日本降书等文件确认，而有法律效果。日本降书是日本官方文件并不代表统派。
7. 日本不管与各国怎么签和约，都不会否认开罗宣言的存在。日本甚至以开罗会议中蒋介石与罗斯福对天皇制的意见，做为目前天皇制应存续的依据。连会议中未列入宣言的事项都承认了，更不会去否认会议宣言。日本天皇制不代表统派。
8. 台湾地位问题: 二战相关国际会议文件方面:日本降书承诺要实行《波茨坦宣言》，《波茨坦宣言》承诺要实行「开罗宣言」，「开罗宣言」明示要将台澎归还给+++国。
9. 战后和约方面:
? 《中日和约》第十条指出台湾澎湖等地人民均成为+++国国民，如果台湾主权属于台湾人民，那么台湾主权即为+++国所有。
? 《中日和约》换文照会第一号指出+++国有效控制的领土均为+++国领土，+++国有效控制台澎，那么台湾主权即为+++国所有。
? +++国没签旧金山和约，而是签中日和约。旧金山和约没提到台独份子的母亲，不代表台独份子的母亲主权未定，《中日和约》第十条已指出台湾澎湖等地人民均成为+++国国民。
? +++国没签旧金山和约，而是签中日和约。旧金山和约没提到台湾主权，不代表台湾主权未定，《中日和约》换文照会第一号指出+++国有效控制的领土均为+++国领土，+++国有效控制台澎，那么台湾主权即为+++国所有。
下面是美国广播人员收到的官方新闻公报,来自日本国立国会图书馆。
CONFIDENTIAL
HOLD FOR RELEASE
PLEASE SAFEGUARD AGAINST PREMATURE RELEASE OR PUBLICATION.
The following communique is for automatic release at 7:30 P.M., E.W.T., on Wednesday, December 1, 1943.
Extraordinary precautions must be taken to hold this communication absolutely confidential and secret until the hour set for automatic release.
No intimation can be given its contents nor shall its contents be the subject of speculation or discussion on the part of anybody receiving it, prior to the hour of release.
Radio commentators and news broadcasters are particularly cautioned not to make the communication the subject of speculation before the hour of release for publication.
STEPHEN EARLY
Secretary to the President
President Roosevelt, Generalissimo Chiang Kai-shek and Prime Minister Mr. Churchill, together with their respective military and diplomatic advisers, have completed a conference in North Africa.
The following general statement was issued:
"The several military missions have agreed upon future military operations against Japan. The Three Great Allies expressed their resolve to bring unrelenting pressure against their brutal enemies by sea, land, and air. This pressure is already rising.
"The Three Great Allies are fighting this war to restrain and punish the aggression of Japan. They covet no gain for themselves and have no thought of territorial expansion. It is their purpose that Japan shall be stripped of all the islands in the Pacific which she has seized or occupied since the beginning of the first World War in 1914, and that all the territories Japan has stolen from the Chinese, such as Manchuria, Formosa, and The Pescadores, shall be restored to the Republic of China. Japan will also be expelled from all other territories which she has taken by violence and greed. The aforesaid three great powers, mindful of the enslavement of the people of Korea, are determined that in due course Korea shall become free and independent.
"With these objects in view the three Allies, in harmony with those of the United Nations at war with Japan, will continue to persevere in the serious and prolonged operations necessary to procure the unconditional surrender of Japan."
下面是该文件图片
