Although widely expected, Donald Trump’s selection of  J.D. Vance as his  running mate is nonetheless profoundly disturbing in its implications for American foreign policy in a Trump presidency. Ronald Reagan and Barry Goldwater are turning in their graves.
Describing the substantive defects in the Trump-Vance approach could fill many pages of newsprint, but – taking Ukraine as an example – both men are disinterested, or openly disdainful, of assisting Kyiv’s defense against Russia’s unprovoked aggression. For Vance, the US lacks both the military assets and the defense-industrial base to be a global power, meaning it must concentrate its resources to defend against China.  
It is beyond debate that years of inadequate defense budgets have made Washington’s job harder. Bill Clinton’s eagerness (along with European governments) to cut military budgets after the Soviet Union’s collapse (the so-called “peace dividend”) and Barack Obama’s debilitating military budget cuts still need repair. But these are failures of will and resolve, typical of Democratic foreign policies, not inadequate assets. Trump should work to correct these deficiencies, not treat them as excuses for further reductions, thereby abandoning even more international positions of strength.
Ironically, Trump rejects Vance’s foundational ‘logic’. He is apparently unwilling even to defend Taiwan. As re centently said: “Taiwan doesn’t give us anything. [It’s] 9,500 miles away. It’s 68 miles away from China…China’s a massive piece of land, they could just bombard it…Taiwan should pay us for defense. You know, we’re no different than an insurance company.”
Isolationism combined with such incoherence is a toxic brew for US national security. But Vance’s nomination has additional implications beyond his and Trump’s poorly conceived statements.  
In Vance, Trump unmistakably named his heir-apparent, which he had heretofore resisted.  Many first-term officials and members of  Congress had hoped for that designation, but their hopes have now been dashed. The new reality may persuade many disappointed aspirants not to serve in a second Trump term.  They know that a VP’s influence in decision-making can be profound, especially when his personal chemistry with the President is as strong as that between Vance and Trump.  Working in the West Wing, just yards away from the Oval Office gives the VP’ a customary advantage of being the last person to speak with a President before a major decision. These advantages are not overcome even by running great Cabinet empires like Defense or State.
Accordingly, the small army of political figures considering becoming candidates for the 2028 Republican presidential nomination might be best served by remaining in Congress or the private sector rather than joining a second Trump term, allowing them to retain their distance in case of disaster in the next four years,  preserving their 2028 viability.
   Moreover, choosing Vance signals that Trump will not be “normalising” his policy or personnel decision-making in a second term. Non-Trump Republicans hoped desperately during his march to the 2024 nomination that a second Trump term would profit from the mistakes of his first. They longed for four years of consistent policy directions and sound implementation, rather than the first’s transactional, unpredictable neuron flashes.  Unfortunately for that dream, and the country, Trump clearly wants no troublesome subordinates, only yes-men and -women. Vance isn’t going to modulate Trump’s behavior.  He is no Mike Pence.
Trump wants undiluted personal loyalty in his post-election government team, at all levels. Vance craved Trump’s endorsement in his 2022 Senate primary, and his help in that year’s general election. He worked for the past two years to get into Trump’s inner circle, adopting his policies as he went.  He has now succeeded. As Chinese Communists describe their relationship with North Korean Communists: Trump and Vance are like lips and teeth.