How Trump Is Undermining GOP Incumbents
Members of Congress typically work hard to represent their districts. In particular, they try to secure benefits that they can bring home and brag about. Constituents wind up hearing good things about their representatives, and therefore tend to vote for them, all else equal. Thus the advantage of incumbency. In the era of partisan polarization, however, that all else equal applies less and less because voters mostly support their partys candidate, so much so that the incumbency advantage seems to be close to disappearing.
But what happens when incumbents actively support policies that take valuable projects away from their districts? Thats whats going on with President Trumps decision to transfer appropriated military funds to pay for his border wall (yes, the one that Mexico was supposed to pay for and that Congress has repeatedly failed to fund).
For now, these transfers appear to be getting plenty of press in the affected states including some with potentially vulnerable Republican senators. If this was a normal failure to win funding for projects, Id say its not a big deal; certainly not something that voters would hold against their representatives. But we cant really say that here. This isnt a missed opportunity its a deliberate effort to take something away that had previously been secured.
https://www.bloomberg.com/opinion/articles/2019-09-06/the-biggest-unknown-about-2020-it-s-not-donald-trump