This website claims to not have news bias, obviously it does. However this editorial piece by William Calhoun demonstrates some journalism you will rarely if ever read on MSM outlets. Mr. Calhoun does not reveal the source for his opinion; however I have read some of these same issues on minor media outlets. It is so minor that I cannot recall them sorry. As to the veracity to the intense cooperation alluded to here I cannot confirm. It is a logical presumption though.
The conclusion of a war with Mexico is a bit of a stretch, at least not an open war. I can see a clandestine war of tit for tat that neither country might feel obliged to publicize.