I don’t want to suggest that presidents are irrelevant to markets and the economy; their actions can and do affect interest rates, and commodity and equity prices. A well-designed stimulus can help blunt the harm of a recession, while policy blunders such as waging unnecessary wars as in Vietnam or Iraq can and will affect markets. But during the ordinary course of business, a president isn't usually an especially important market-moving agent.This article does a nice job of explaining the connections between presidential politics and economic performance. Clinton proposed an increase on government spending that might expand an economy in recession. The economic boom during her husband's administration was unrelated to his economic policies. Changes in the market created created the boom. Trump's claim that cutting taxes for the rich and easing regulation has not proven to be a good recipe for economic growth. Putting tariffs on imports has typically caused economic contractions. On the other hand, he regarded it as a good way to convince citizens who have not benefited from globalization to vote for him.
The bottom line is that voters should not pay much attention to claims made by presidential candidates about how they will create jobs and grow the economy. They learn more important things about the candidates during election campaigns. Trump's campaign has collapsed because he has been exposed during the election cycle.