This is my summary of a discussion raised in Hebrew on the viewpoint of the Chafetz Chaim concerning is it permitted for those who are impure because of contact with the dead to ascend the outer parts of the Temple Mount, after purifying themselves from other forms of impurity.
The original discussion in Hebrew is found at
http://www.inn.co.il/Forum/Forum.aspx/t747044In his brief summary of commandments that are applicable today in Sefer Hamitzvot Hakatzar, the Chafetz Chaim who has much authority in halachic questions wrote the following.
קצג. מצות לא תעשה שלא יבוא טמא למחנה לויה הוא הר הבית. שנאמר: "כי יהיה בך איש אשר לא יהיה טהור וגו' לא יבוא אל תוך המחנה" (דברים כג, יא). וקבלו חז"ל (פסחים סח) שהוא מחנה לויה והוא הר הבית, וטמא שעבר על זה ונכנס להר הבית עובר בלאו זה. ונוהג גם בזמן הזה בזכרים ונקבות כיון שאנו טמאי מתים.
Translation, Negative commandment 193. That one should not enter into the Levite camp, this is the Temple Mount, for it was stated if there be a man among you who is not pure, etc. he shall not come into the camp (Deut. 23:11). And the sages received a tradition (Pesachim 68) that this is so for the Levite camp and this is so for the Temple Mount, and the impure who transgressed this and entered into the Temple Mount violated this prohibition. And it is applicable also at this time to both males and females because we are defiled by contact with the dead.
In another book by the Chafetz Chaim he implies that someone who is defiled by having come into contact with the dead but is otherwise pure is allowed into the outer part of the Temple Mount.
The source given by the forum sited above is Shmirat Halashon Vol.2 Chapter 16.
בספרו שמירת הלשון (חלק ב פרק טז), הוא עצמו כותב על פי הגמרא, כי טמא מת משולח רק אל מחוץ למחנה השכינה (העזרה), ואילו הזב משתלח אל מחוץ למחנה לויה (הר הבית).
The forum I cited also brings the views of the Chafetz Chaim in Likutei Halachot, Sota page 20 to back the more lenient understanding.
The conclusion of that forum what the Chafetz Chaim meant when he said in the first source, Sefer Hamitzvot Hakatzar, that there is a prohibition to go to the Temple Mount in our days, because we are defiled by the contact with the dead, has to be explained a little less literally. What he means is that because in general we are contaminated with the special impurity that comes by contact with the dead, we are not in general, well versed in purity laws. If one goes to the outer parts of the Temple Mount and does not follow the other purity laws under normal circumstances he or she would be violating this prohibition.
Now commenting on what the forum said.
The debate then concerning going to the Temple Mount in our times if we only concern ourselves with the issue brought up by the Chafetz Chaim would revolve around 2 questions. Is today's situation classified as normal circumstances and secondly can we obtain the knowledge if we receive detailed education on the subject to observe all the other purity laws to go in at least to the outer parts of the Temple?
If one knows of a better way to resolve the seeming contradiction between the works of the Chafetz Chaim please post.