In terms of law... it really all depends on what the USSC does... if they let this ruling stand, well then it's unconstitutional by interpretation. But from a pure constructionist standpoint, there is nothing specifically unconstitutional about an all male draft since the draft is not specifically a constitutional requirement. It is required as a function of congress' right to raise and support armies, and since HOW this happens is not specifically stated, then the interpretation in 1918 is that congress can make laws to do this, which they did in Article I, Section 8 of the United States Constitution and 10 U.S. Code § 246. The 14th Amendment baring involuntary servitude would include conscription was rejected.
Had the Equal Rights Amendment passed, then an all male draft would be unconstitutional, without this then rights... defined by the constitution, deals with things the Government can not do to people, not SHOULD be done to people. Treating the draft, like people have the RIGHT to be drafted would be a dramatic departure judicial review history. Do women have the RIGHT to be drafted? That is an absurd argument. The government has the right to seize property in the interest of eminent domain. Does that mean because the US takes property from someone that automatically everyone that owns property anywhere has the right to have their property taken? It is something that can happen based on need.... if the government NEEDS to put women in uniform, they have the right to do this... but they do not have to if they don't want to.