Comparing the basicity of aniline and ortho anisidine

In my worksheet there is a question that asks for the comparison of basicities of the three anisidine isomers and aniline:


[![enter image description here](https://i.stack.imgur.com/vreZn.png)](https://i.stack.imgur.com/vreZn.png)


After my analysis using: 


$\text{Basicity} \propto \text{+M effect (except for meta annisidine)} \propto \dfrac{1}{\text{-I effect}}$,


I could make the following conclusions:


1. m-anisidine should be the least basic
2. p-anisidine should be more basic than aniline.


But the main problem is comparing the basicity of aniline and o-anisidine and comparing them with p-anisidine. I doubt the presence of [ortho effect](https://chemistry.stackexchange.com/questions/7683/ortho-effect-in-substituted-aromatic-acids-and-bases) in ortho isomer after seeing the [ball and stick model](https://en.wikipedia.org/wiki/O-Anisidine#/media/File:O-Anisidine_3D_ball.png) which makes the interaction of lone pair of nitrogen with hydrogen atoms of $\ce{-OCH3}$ improbable. 


The answer given is: 



> 
>  p-anisidine> aniline > o-anisidine > m-anisidine (I have verified it with $pKa$ values from [PubChem](https://pubchem.ncbi.nlm.nih.gov))
> 
> 
> 




**Why you considering the methyl group on $\ce{-OCH3}$ to be "locked" in position, facing away from the $\ce{-NH2}$ group?** It is free to rotate in all directions, and it *will* come at a position next to the $\ce{-NH2}$ group, where the ortho effect will apply. 


For a visualization, here is a similar image:


![](https://i.stack.imgur.com/QiMIR.gif)


(*taken from [Martin's excellent post](https://chemistry.stackexchange.com/a/89920/5026)*)




---


**PS:** I believe that Steric Inhibition of Resonance should not be invoked here, because *both* sides of the $\ce{-NH2}$ group are not blocked by the $\ce{-OCH3}$ group, and $\ce{-OCH3}$ is certainly not as bulky a group as *t*-butyl.


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