I think a voter-id card with chip will likely be one part of the solution, with a more friendly Supreme Court it should be possible for a Conservative state to implement. This will help prevent that state from turning blue due to corruption/fraud.
Every one has to apply for a voter-id card (and renewed every four years), it will have photo and will require birth certificate, or naturalization certificate.
At election time each registered voter is sent an election-card that has a bar-code tied to that voter, it will show polling location etc.
On election day, the voter takes their election-card and voter-id card to the polling station, the staff scans the election-card and voter-id card and the data should match. The data is then transmitted electronically to a central site (per state). This prevents the same person voting twice. The election-card is dropped into a sealed box.
The voter gets their ballot, fills it out and drops it into a sealed box.
At the end of the day the number of ballots and election-cards are counted, they should be the same for each polling station.
The number of votes cast in the state (that were stored electronically) should match all the ballots and election cards from every station.
Multiple states can then compare the voter-ids from their votes to ensure the same person did not vote in multiple states/elections.
I already have a real ID New Hampshire drivers license. I had to bring in my passport, a bill with my home address and my Social Security card. There were three different types of ID required. Some required 2 examples. I was told these will be required within the next few years to board a domestic airline flight. I do not know why this could not be required to vote. Then record your drivers license number to a specific ballot serial number. Problem solved.
Now, all you have to do is get it through congress. Good Luck.