In the United States, really the only election that "counts" per se is the Primary ones, and only if you live in certain states.
Now that Iowa and New Hampshire are behind us, l will use this an example. Mind you, I am not suggesting that I am voting for any of these candidates, simply pointing out what so many don't seem to understand.
Iowa: Cruz, Trump, Rubio, Sanders, Clinton.
New Hamphsire: Trump, Kasich, Cruz, Sanders, Clinton.
Initially, perhaps Carson was a good candidate or perhaps Huckabee, but because the voters in two states did not vote for them, then they will not be invited to any more debates and their race is essentially over. If you live in South Carolina, you might have more choices. Maybe. So where, in total, 20% of voters support candidate A, if only 2% of voters support candidate A in Iowa or New Hampshire, he will be out of the race and you will have to choose a new candidate.
By the time my state votes on April 26, the list of candidates will likely be down to two and it is very unlikely at that point that my vote will count anyway.
Since the President is chosen in this country by electoral college votes, unless you live in a so-called battle-ground state, it is very likely you vote will not matter anyway. Since I live in PA, whether I vote for a Republican or Independent or write-in candidate, it will not matter. The state always leans blue and winner takes all 20 electoral votes. Period.
This year there are 7 battle-ground states: NH, OH, VA, FL, IA, CO, and NV. These are really the only voters that matter. This makes up 85 electoral votes up for grab. The Democrat candidate only needs 23 of those to win the election, as Democratic states in past elections rarely ever change to Republican. They could, but rarely. Republicans MUST hold on to all the states that traditionally vote Republican AND somehow sway 64 more electoral votes. Not impossible, but a difficult task.
If you live in OH, FL or VA, you probably have a really good shot at keeping Hillary Clinton or Bernie Sanders from destroying what is left of this country. I would say, in your case, perhaps voting for an unworthy candidate to keep a truly evil candidate from winning, might be something worth praying about.
Honestly, I don't know why this is so hard to grasp. It is very likely that your vote doesn't count for two cents. Really. And if your choice is between Trump and Cruz or Rubio, you might want to consider who actually has the best chance of winning those battle ground states in the first place.
The folks in New Hampshire, a battle ground state, threw their support behind Trump and Kasich and that state leans Republican in the presidential election. Just something to think about.....