Since 1970 we have had 25 years under a republican P and 12 years under a dem P. Theres a lot of good and bad like everything else.
Presidents may provide leadership, but as one person representing only the Executive branch, a president cannot totally drive the policies of the nation. For instance, Congress taxes, and Congress spends. The president either signs or vetoes the bills, in their entirity.
Of the three branches of government, Congress, and more specifically the House, more accurately represents the aggregate of the people than the Executive, and definitely more than the Judiciary. Since the change to statewide elections of Senators, that section of Congress has been more 'beltway' driven than 'home-state' driven.
The overall political trends through recent decades are the culprit for the problems of today and tomorrow, not "a" particular individual, nor "a" particular party or group.
Granted, the way out of the abyss will require strong leadership (not "a" particular leader), and the combined efforts of a majority of voting citizens. Many of those leaders are currently being shaped, and will be shaped, in the ongoing Islamic War against Civilization, and the unspoken War Against American Citizens by globalists of every stripe.