Saudi Arabia's continuing campaign against al-Qaeda-inspired terrorism has enjoyed considerable success. The atmosphere in the country is noticeably more relaxed than it was a few years ago when the kingdom was buffeted by several major suicide bombings.
But the arrest earlier this month of eight men accused of plotting terror attacks in Riyadh and Jeddah is proof that the campaign is not over. As one Saudi newspaper editorial put it: "Renewed vigilance is required."
Of the eight men arrested in the latest sweep, two were Saudis and the other six were Yemenis. There seems little doubt that the terror plot was hatched in Yemen.
It is well known that al-Qaeda supporters are exploiting the lawlessness in that country to set up bases. But even if order were to be restored to Yemen, Saudi security officials would still need to be vigilant: the war in Syria is giving impetus to al-Qaeda groups there, and energizing jihadists in Iraq.
Tightening border controls is only part of the solution. Saudi officials know they also have to take steps at home to discourage their own young men from being lured into groups advocating the use of violence in the name of Islam.
For since the monstrous 9/11 World Trade Centre attacks in 2001 and up to the failed plot in the kingdom earlier this month, a surprising number of Saudi nationals have been associated with terror incidents.
Trouble on the borders
The Saudi authorities' attempts to eliminate al-Qaeda, and thereby remove its potential attraction to the kingdom's disaffected young men, have been greatly hindered by developments beyond the country's borders.
The absence of a strong central government in Yemen has given al-Qaeda, despite frequent US drone attacks, the freedom it has been looking for.
Furthermore, jihadist leaders are unequivocal about their aims.
Earlier this year, an Islamist website called on Muslims to "do everything possible to strengthen the jihadist front in Yemen as it serves as a source of back-up and reinforcement for operations in the Land of the Two Mosques [Saudi Arabia]."
Some Muslims are heeding the call. Just last week, the Yemeni authorities arrested two Egyptians who had entered the country illegally, en route to Saudi Arabia.
The Saudi government's concern is that the war in Syria and rising sectarian tension in Iraq will provide yet more recruiting and training opportunities for al-Qaeda, creating more threats to the kingdom.
'New and decent lives'
The challenge, as ever, will be to convince young Saudis of the folly and danger of attaching themselves to jihadists.
Many Saudis remain mystified by the apparent appeal of such groups.
Writing in the daily al-Watan, columnist Yahya al-Amir wondered "why Saudi youth follow calls to jihad, fighting and seeking martyrdom more than anyone else".
He concluded that changes were needed to religious education in the kingdom, making a clear distinction between Wahhabi Salafi doctrine on the one side, and that of jihadist Salafis advocating violence on the other.
For example, he said, the concept of jihad was "a vital idea of value in Islam", but had been presented out of context in an absolutist way by jihadists.
Saudi authorities have made some progress in re-education.
As another columnist pointed out, "an enlightened attitude to the rehabilitation of those who have been duped into supporting the bigoted ideas of al-Qaeda has led to a small but significant number of captured terrorists rejecting their evil past and seeking to live new and decent lives in society."
The problem is that new potential al-Qaeda recruits are emerging each day in the form of disillusioned young Saudis with no jobs and meagre prospects of employment.
One reason for this is that many job-seekers lack practical skills.
Saudi Arabia's Deputy Minister of Labour Mofarrej al-Haqbani admitted in a speech last May that the education system was out of step with the demands of the market place.
"We have to deliver improved standards of training and education. I have to say here that in Saudi Arabia the majority of students after high school turn to study literary and theoretical disciplines", Mr Haqbani said, rather than technical and applied ones. "
"It is one of our major challenges," he added.
Schemes providing financial incentives for job-seekers have so far enjoyed only limited success. The same is true of the "Nitaqat" programme that requires all businesses to employ a 30% quota of Saudi nationals.
Adding to the problem is the prevailing expectation amongst Saudi youth that they should accept nothing less than a comfortable job in the civil service.
So Saudi Arabia's campaign against al-Qaeda is likely to continue for some considerable time. Only a foolhardy gambler would bet on when stability will return to Yemen, Syria and Iraq - and when every young Saudi has a job.