If "grubby power-grab" it is, you've just described the governments of most of Europe. Even allowing for unpredictability, are you really saying some Tory MP's (or anyone) would facilitate a much grubbier power-grab by brexit supporting Labour? Even if they did, they'd need support of SNP (indyref 2 wa hae!) AND lib-dem AND DUP AND everyone else and even then they wouldn't have a majority. If you think there's a funding crisis now, how much would be left for defence after all the bungs and bribes needed to hold that lot together?