It's not a matter of engaging in backflips or acrobatics. It's a matter of reading provisions of the Constitution in historical context, not interpreting every provision in the broadest possible way in which it could be interpreted, and handling tensions between Constitutional provisions through balancing instead of just picking our favorite provision and giving it maximal effect.
1) Free speech zones: At the time of the founding, state police power was considered nearly unlimited, and the First Amendment didn't apply to the states at all. So how do you reconcile the state's police power with the right of people to peacefully assemble? The answer does not have to be "you have to read the right to assemble in the broadest way possible to the exclusion of any legitimate state interest in policing." That's one mode of interpretation, but that's not the only justifiable one.
2) The Adam Walsh Act. Not an ex post facto law because it doesn't directly change the criminal status of any person, but rather directs, optionally, states to conform their registration laws to certain standards. Many states do not have ex post facto clauses in their state Constitutions. See: http://congress-courts-legislation.blogspot.com/2011/01/stat....
3) Iraq War: The Constitution does not say that Congress must declare war before any hostilities are initiated. It just says that "The Congress shall have Power... To declare War..." Absent much guidance as to what this provision means, we can look to historical practice. And almost immediately we see that no formal declaration of war (whatever that is--the Constitution never uses the term) was considered necessary when presidents of the founding fathers' generation engaged in hostilities with Tripoli and Algiers, within just a few decades of the founding.
This is not to try and convince you of these points. Rather, it's an attempt to show that reasonable minds may differ. Conservative views of Constitutional interpretation are not illegitimate ones, and indeed are informed by the basic mode of common law legal interpretation that the founders themselves were familiar with.