The phrase "a border that was" is correct and usable in written English.
It can be used when referring to a border that existed in the past or describing a situation related to a border that has changed or no longer exists.
Example: "The treaty established a new boundary, replacing a border that was once a point of contention between the two nations."
Alternatives: "a boundary that existed" or "a border that used to be".
Access into Gaza and trade across a border that was once hermetically sealed by Israel are growing.
I know we have to have borders, but I wish we could have a border that was more open and fluid".
Such an Afghanistan, Pakistani leaders fear, will lay claim to the Pashtun areas that straddle a border that was drawn carelessly by the British and that Afghanistan has never fully accepted.
A senior Eritrean official, Yemane Gebreab, said earlier that thousands of Ethiopian soldiers had been killed at the western front of the fighting along a border that was never clearly defined, and that seven tanks had been destroyed.
After the 1967 Arab-Israeli war, he tried to organize guerrilla warfare in Lebanon, but gave up and returned to Jerusalem, swimming the Jordan River to evade Israeli troops along a border that was not yet secured.
But late last week, Ukrainian border guards abandoned a post near Luhansk, blowing a hole in a border that was already considered porous at best, opening the way for men, war matériel and contraband to enter the country.
"We have a border that's so porous that anyone can walk across it.
With a border that is rugged and largely unmarked, the risk of fire being misdirected by accident is always present.
Then again, they may have disapproved of tank and aircraft movements too close to a border that's still disputed.
What I'm telling you is that we're going to have a border that is smart and secure.
Their work showed, he said, "that you can have a border that is attractive, that doesn't obstruct the city, but that also provides security".
