Having trouble merging/joining two datasets on two variables in R - r

Question

I realize there have already been many asked and answered questions about merging datasets here, but I've been unable to find one that addresses my issue.
What I'm trying to do is merge to datasets using two variables and keeping all data from each. I've tried merge and all of the join operations from dplyr, as well as cbind and have not gotten the result I want. Usually what happens is that one column from one of the datasets gets overwritten with NAs. Another thing that will happen, as when I do full_join in dplyr or all = TRUE in merge is that I get double the number of rows.
Here's my data:
Primary_State Primary_County n
<fctr> <fctr> <int>
1 AK 12
2 AK Aleutians West 1
3 AK Anchorage 961
4 AK Bethel 1
5 AK Fairbanks North Star 124
6 AK Haines 1
Primary_County Primary_State Population
1 Autauga AL 55416
2 Baldwin AL 208563
3 Barbour AL 25965
4 Bibb AL 22643
5 Blount AL 57704
6 Bullock AL 10362
So I want to merge or join based on Primary_State and Primary_County, which is necessary because there are a lot of duplicate county names in the U.S. and retain the data from both n and Population. From there I can then divide the Population by n and get a per capita figure for each county. I just can't figure out how to do it and keep all of the data, so any help would be appreciated. Thanks in advance!
EDIT: Adding code examples of what I've already described above.
This code (as well as left_join):
countyPerCap <- merge(countyLicense, countyPops, all.x = TRUE)
Produces this:
Primary_State Primary_County n Population
1 AK 12 NA
2 AK Aleutians West 1 NA
3 AK Anchorage 961 NA
4 AK Bethel 1 NA
5 AK Fairbanks North Star 124 NA
6 AK Haines 1 NA
This code:
countyPerCap <- right_join(countyLicense, countyPops)
Produces this:
Primary_State Primary_County n Population
<chr> <chr> <int> <int>
1 AL Autauga NA 55416
2 AL Baldwin NA 208563
3 AL Barbour NA 25965
4 AL Bibb NA 22643
5 AL Blount NA 57704
6 AL Bullock NA 10362
Hope that's helpful.
EDIT: This is what happens with the following code:
countyPerCap <- merge(countyLicense, countyPops, all = TRUE)
Primary_State Primary_County n Population
1 AK 12 NA
2 AK Aleutians East NA 3296
3 AK Aleutians West 1 NA
4 AK Aleutians West NA 5647
5 AK Anchorage 961 NA
6 AK Anchorage NA 298192
It duplicates state and county and then adds n to one record and Population in another. Is there a way to deduplicate the dataset and remove the NAs?

Answer 1

We can give column names in merge by mentioning "by" in merge statement
merge(x,y, by=c(col1, col2 names))
in merge statement

Answer 2

I figured it out. There were trailing whitespaces in the Census data's county names, so they weren't matching with the other dataset's county names. (Note to self: Always check that factors match when trying to merge datasets!)
trim.trailing <- function (x) sub("\\s+$", "", x)
countyPops$Primary_County <- trim.trailing(countyPops$Primary_County)
countyPerCap <- full_join(countyLicense, countyPops,
by=c("Primary_State", "Primary_County"), copy=TRUE)
Those three lines did the trick. Thanks everyone!