Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_67 (date VARCHAR, sample_size VARCHAR, democrat VARCHAR, republican VARCHAR, poll_source VARCHAR)

### Question ###
What is the date that the polls were going on at quinnipiac when john mccain was the republican, barack obama was the democrat and the sample size was bigger than 1427?

### Accurate SQL ###

SELECT date FROM table_name_67 WHERE republican = "john mccain" AND poll_source = "quinnipiac" AND democrat = "barack obama" AND sample_size > 1427