From the moment he was sworn in, President Trump faced a personnel crisis, starting virtually from scratch in lining up senior leaders for his administration. Seven weeks into the job, he is still hobbled by the slow start, months behind where experts in both parties, even some inside his administration, say he should be.

The lag has left critical power centers in his government devoid of leadership as he struggles to advance policy priorities on issues like health care, taxes, trade and environmental regulation. Many federal agencies and offices are in states of suspended animation, their career civil servants answering to temporary bosses whose influence and staying power are unclear, and who are sometimes awaiting policy direction from appointees whose arrival may be weeks or months away…

Mr. Trump’s personnel problems are rooted in a dysfunctional transition effort that left him without a pool of nominees-in-waiting who had been screened for security and financial problems and were ready to be named on Day 1. In the weeks since, the problem has been compounded by roadblocks of his own making: a loyalty test that in some cases has eliminated qualified candidates, a five-year lobbying ban that has discouraged some of the most sought-after potential appointees, and a general sense of upheaval at the White House that has repelled many others…

In the vast majority of cases, Mr. Trump’s administration has not even begun the lengthy screening process — which can take several weeks to as long as two months — that nominees must complete before their confirmations can be considered by the Senate. According to data obtained by The New York Times, the Office of Government Ethics, the independent agency that conducts financial reviews of every presidential nominee, had received only 63 disclosure reports for prospective Trump administration nominees as of March 5, less than a third of the 228 that Mr. Obama’s team had submitted by that date in 2009.