In the present (as of 11/6/2019) political climate, with a Democratic House of Representatives getting ready to impeach a Republican president, this is a particularly difficult question to answer. Levels of bipartisanship are at record lows in the American political system, with more clear blue water between the political parties than ever before. Under such circumstances, it's difficult to detect any real similarities between Democrats and Republicans.

Nevertheless, and speaking in the broadest possible terms, one could argue that the two parties have similar, if not identical, long-term goals but differ radically in how to achieve them. For instance, both Democrats and Republicans want the United States to be a prosperous country. However, whereas Democrats favor more government intervention in the economy to bring about this particular goal, Republicans opt for a more hands-off approach, arguing that prosperity comes through government getting out of the way and allowing businesses to make their own decisions wherever possible.

Continuing with the economic theme, one could also say that Democrats and Republicans alike are generally supportive of a capitalist economy. Though a handful of prominent Democrats, such as Representative Alexandria Ocasio-Cortez, are avowed socialists, most Democrats remain committed to the capitalist system, albeit one that is dramatically reformed to operate more effectively for working people.

Traditionally the party of big business, the Republicans are also wedded to the capitalist system, which they regard as being the best means of achieving prosperity. However, even some Republicans have argued that the current system doesn't work effectively, which is why they've put forward proposals that establish tariffs on some imported goods, especially from China, as a way of protecting American jobs and businesses.

Though such proposals may differ from those of the Democrats in terms of substance, they nonetheless share with the Democrats an impatience at how capitalism has developed, especially in relation to its impact on American workers.

Democrats and Republicans make up the two major parties in American politics, and it is very hard to be elected to public office without identifying with either one.  Both parties wish to see a strong American economy.  Both parties are hostile toward enemies of the United States.  While it is more rare now than in the past, the two parties can agree on some things in a bipartisan manner.

 Both parties spend billions of dollars yearly on elections.  Both parties have armies of pollsters which canvass the American people in order to gauge popular opinion.  Both parties encourage pundits and editors to create news articles from the party's point of view.  This has been going on even before the formation of cable news; newspapers during the nineteenth century could be openly partisan.  Special interest groups have prominent roles in both parties through fundraising and super PACs.  

Listing to the discord between the Democrats and Republicans, it would appear that it would be very difficult to find any similarities between the two parties. However, there are similarities between the two parties even though how they would go about achieving the goals differs.

Both parties want the United States to be viewed as a strong country in world affairs. They want countries to know our word means something. Both political parties want peace to exist throughout the world. They want the United States to have good relations with other countries, but not unconditionally. For example, both parties want peace in the Middle East. This peace must be reasonable for all parties involved. While they differ on how that should be achieved, they do want peace to exist.

Both parties want our economy to be strong and to grow. They want low unemployment rates, they want businesses to invest in the economy, and they want fair trade policies. While there are major differences in how to achieve these goals, the goals are similar for both parties.

Both the Republicans and the Democrats want the United States to be a great country, one that can be trusted, one that is growing in economic terms, and one that is respected around the world. Both parties express a love for our country and want to see the country and its people prosper.