China has sent a growing number of high-altitude balloons near Taiwan in recent days as it steps up pressure on the self-governing island after it held elections this month in defiance of China's claims of sovereignty.

Why it matters: It’s part of a larger intimidation effort that Taiwan's defense ministry has called "cognitive warfare" — an attempt to weaken the resolve of Taiwan's residents and leaders and bring their behavior more in line with Beijing's will.

What's happening: China sent six high-altitude balloons near and over Taiwan earlier this week, the highest number Taiwan's Ministry of National Defense has reported in a day.

• The balloons come in addition to incursions by Chinese military planes and ships across the Taiwan Strait, which have occurred on a near-daily basis since then-House Speaker Nancy Pelosi visited Taiwan in 2022.
• China also sent a flurry of balloons over Taiwan just days before the country's presidential election on Jan. 13, when Taiwan elected current Vice President William Lai to be the next president. His victory gives the Beijing-skeptic Democratic Progressive Party (DPP) an unprecedented third straight term holding the presidency.
• Chinese officials had previously warned Taiwanese against voting for Lai.

Some view the timing of the balloons as attempts to sway the minds of Taiwan's voters and to pressure Taiwan's government.

• "Balloons provide an additional way for China to challenge Taiwan's control of its air space," Bonny Lin, director of the China Power Project at the Center for Strategic and International Studies, told Axios.
• "Balloons also have more reach — China has also been able to send balloons directly over Taiwan without much response from Taiwan. In contrast, China has yet to send manned or unmanned military aircraft over the main island of Taiwan," Lin said.
• Taiwan's Ministry of National Defense has previously said its general policy has been to not shoot down the balloons. It has previously assessed some balloons as being primarily meteorological in use.

What they're saying: China has not commented on the balloons' function or purpose.

• "I'm not aware of the specifics you mentioned and it's not related to China's foreign affairs," Chinese embassy spokesperson told Axios in an email when asked for more details about the balloons.

Between the lines: China is trying to walk a fine line between putting pressure on Taiwan and sparking a wave of public support for the DPP as it is still negotiating with two other political parties for control of the legislature, Raymond Kuo, director of the RAND Corporation's Taiwan Policy Initiative, told Axios.

• Because the balloons don't appear to carry munitions, they're a "relatively less escalatory way to put pressure while controlling the blowback," Kuo said.

Background: China's high-altitude surveillance balloons first drew major international scrutiny in February 2023, when a balloon passed over the continental U.S.

• The incident pushed U.S.-China relationship to its lowest point in decades. Secretary of State Antony Blinken canceled a planned trip to Beijing, and China refused to take a call from Defense Secretary Lloyd Austin after a U.S. fighter jet shot down the balloon once it reached open water.
• The U.S. said the balloon was "clearly for intelligence surveillance." The Chinese government has said the balloon was used for meteorological purposes only.
• Shortly after this incident, Taiwan and Japan revealed that Chinese balloons had also passed near their territory in recent years.

What to watch: "By flying balloons over Taiwan, Beijing leaves escalation space. In the future, they can increase by steps: first fly balloons, then drones, then fighter aircraft between 12 and 24 [nautical miles] from Taiwan's coast, then inside Taiwan's territorial airspace, and potentially next fly fighters over Taiwan," Bonnie Glaser, managing director of the German Marshall Fund's Indo-Pacific program, told Axios.

• "The Chinese likely want to ratchet up pressure gradually and leave options for future responses," Glaser said.

Editor's note: This story has been updated to include a quote from the German Marshall Fund's Bonnie Glaser.